U.S. forces opened an assault on Iraq early today with a barrage of 40 Tomahawk cruise missiles that slammed into three targets around Baghdad in an attempt to hit President Saddam Hussein, military officials said.

Radar-evading F-117A stealth aircraft also dropped 2,000-pound bombs in the first phase of an onslaught intended to end Hussein's rule. The attack appeared to be aimed at a residence in southern Baghdad where intelligence reports had pinpointed Hussein, officials said.

But three hours after the bombing, Hussein appeared on Iraqi state television, looking subdued and puffy and wearing a military uniform. Reading from a text, he vowed that Iraq would "stand up to the evil invaders" and added, "They will face a bitter defeat."

The salvo of cruise missiles was fired from six Navy ships -- three cruisers, a destroyer and two submarines -- in the Persian Gulf and Red Sea, Navy officials said.

Rear Adm. John M. Kelly told reporters on the USS Abraham Lincoln that most of the missiles headed toward their targets, but one missile failed on launch. He said Operation Iraqi Freedom was underway as warplanes took off from the carrier.

Explosions and antiaircraft fire erupted in the Iraqi capital at dawn. At the same time, armored vehicles of the U.S. 3rd Infantry Division began moving into position to cross a sand berm into Iraq from Kuwait. Many of the 250,000 U.S. and British forces in the region began forming into what were termed "ground assault convoys" along the Iraq-Kuwait border in preparation for the invasion.

On Wednesday, U.S. forces had prepared the battlefield by intensifying bombing and stepping up reconnaissance operations inside Iraq. These operations were carried out by an unknown number of Special Operations troops and specialized Marine and Army units, U.S. defense officials said. They were accompanied by a series of U.S. airstrikes across the breadth of southern Iraq, from the Jordanian border in the west to near the Iranian border in the east, the U.S. Central Command announced. The airstrikes across the south continued early this morning, officials said.

The Wednesday airstrikes hit nine targets, including two long-range artillery emplacements and one surface-to-surface missile system, deployed between the Kuwaiti border and the city of Basra, 35 miles to the north, the Central Command said. Those targets were hit because U.S. commanders worry that the U.S. invasion force assembling in northern Kuwait is at its maximum vulnerability to attack by chemical weapons.

A senior defense official characterized those airstrikes as one of the heaviest bombings conducted in the two "no-fly" zones in Iraq since the areas were created after the Persian Gulf War in 1991. They continued a pattern of using enforcement of the no-fly zones as a way to bomb targets whose destruction is deemed useful in preparing for the full-fledged U.S. push into Iraq that now seems imminent.

As the U.S. teams maneuvered on the northern side of the border, 17 Iraqi soldiers crossed to the south to surrender to Kuwaiti authorities and U.S. forces, U.S. military officials said. The officials said the soldiers, believed to be first Iraqis to surrender in the conflict, were handed over to Kuwaiti authorities. They were not deemed prisoners of war, the officials added, because the war has not formally begun.

A number of Iraqi military officers also arrived in the region of northern Iraq under Kurdish control and turned themselves in to Kurdish militia officers, according to Al Hayat, a London-based Arabic newspaper with a correspondent based in the zone. Similarly, a Pentagon official said Iraqi dissenters inside the country have begun speaking to U.S. intelligence personnel over open telephone lines about troop movements and possible locations of biological or chemical weapons caches.

While several U.S. military units were observed edging closer to the border, the most significant movement was made by the 3rd Infantry Division. Maj. Gen. Buford C. Blount III, the division commander, ordered his 20,000 soldiers and 10,000 tanks, armored vehicles and fuel trucks to line up close to the border in snaking columns.

The 1st Marine Expeditionary Force, meanwhile, was poised to attack toward Basra, along with British marines and Army units accompanying them and assigned to occupy the city after the hostilities cease.

Across numerous military camps that have sprouted in the northern half of Kuwait, signs of the impending war could be seen through a swirling, sulfur-colored cloud of dust. At Camp New Jersey, about 100 officers with the 101st Airborne Division gathered for more than three hours in a large yellow tent to study a 500-square-foot, makeshift terrain map of southern Iraq.

The division has nearly 260 helicopters, and much of the discussion revolved around how best to position and refuel those forces. An intense sandstorm grounded attack helicopters Wednesday, however, and forced many soldiers to strap on plastic goggles. Flags tied to tank turrets whipped in the wind. But the wave of fine dust did little to hinder military activity across the Kuwaiti desert.

Engineers reinforced bunkers built from shipping containers and sandbags designed to protect troops from retaliatory Iraqi missile attacks. Ammunition was distributed to infantry and artillery units. "Breach lane marking" diagrams were taped on inside doors of portable toilets to encourage those who will drive across the border to memorize the configuration of lights and signals marking lanes through Iraqi minefields.

Soldiers packed their trucks and Humvees, lashing barracks bags and Meals Ready to Eat cases with such top-heavy ingenuity that one officer at Camp New Jersey compared his soldiers to the Clampetts, the rustic migrants in "The Beverly Hillbillies."

In the nearby Persian Gulf, combat pilots aboard the aircraft carrier USS Theodore Roosevelt were ordered to sleep during the day Wednesday to prepare for nighttime operations. British sailors were told their beer rations would stop, which many regarded as a sure sign of impending hostilities.

Rallying the U.S. troops, Lt. Gen. William S. Wallace, who commands the Army's V Corps, exhorted them with a hand-held microphone Wednesday. " I know that no soldier really wants to go to war," he said. "We are left with no alternative."

The convergence of forces in what the military calls tactical assembly areas in northern Kuwait has provoked constant anxiety about keeping them untangled, both on the ground and in the air. At one bustling helicopter base, Col. Gregory P. Gass, commander of the 101st Aviation Brigade, said: "Right now, my biggest concern is this airfield. It's so crowded, so many aircraft here, that getting in and out is a nightmare."

Across Kuwait, the tiny desert emirate serving as a launch pad for war, signs of imminent military action were everywhere. Checkpoints appeared on once-open roads Wednesday afternoon. On the smooth paved highways, a convoy of Patriot missile trucks shared the road with the late-model luxury cars favored by Kuwaitis.

With the sound of military planes roaring overhead and the last civilian flights for Europe having left, some Kuwaitis made last-minute purchases of gas masks, lined up at ATMs and gas stations, and stocked up on bottled water. For many, the chief concern was Kuwait's preparedness to deal with the consequences of a possible chemical attack.

"I cannot say we are 100 percent fully prepared," said Sami Faraj, a military expert advising the Kuwait government on dealing with such an attack. "But we can report that we are ready."

The invasion force here is one-third smaller than that assembled a dozen years ago in the Persian Gulf War that liberated Kuwait from seven months of Iraqi occupation. The international coalition this time is also far smaller, limited mostly to a British force totaling more than 40,000 in the region, about 25,000 of whom are in Kuwait and will move into Iraq alongside U.S. Marines. Altogether, the land force gathered here consists of about 130,000 Americans, including just under 70,000 Marines, more than 20,000 soldiers from the Army's 3rd Infantry Division, more than 20,000 from the 101st Airborne and others from a variety of support units.

Military officials have described an audacious war plan in recent weeks, including a fast push toward Baghdad. Led by the armor-endowed 3rd Infantry, the Army anticipates surging through several of the dozen freshly carved cuts in the sand berm separating northern Kuwait from Iraq as tens of thousands of Marines also roll forward.

An initial goal will be Basra and the principal Iraqi port, Umm Qasr at the head of the Persian Gulf. The Marines and the British are expected to take the lead in that assault, while other components of the U.S. ground force begin the race north.

The United States has engaged in a massive leaflet drop in recent days across southern Iraq, urging Iraqi soldiers to lay down their arms and Iraqi civilians to stay at home. Iraqi troops, one leaflet said, should "not risk their life and the life of their comrades," but instead should "leave now, go home, and learn, grow, prosper."

Air Force officials reported that for the first time coalition aircraft on Wednesday dropped leaflets providing specific "capitulation" instructions to Iraqi forces, describing what actions they could take to sit out the hostilities.

Another leaflet warned that Iraqi commanders "will be held accountable for noncompliance" if they use weapons of mass destruction. The top commander of U.S. ground forces, Army Lt. Gen. David D. McKiernan, told reporters that any Iraqi use of chemical weapons would draw a "dramatic" response. He did not say what it would be, but added: "It would be a hugely bad choice on the part of any Iraqi leader or commander to employ chemical weapons."

One Army commander put the odds of Iraq possessing chemical weapons at "80 to 90 percent," but there still is no consensus on whether those weapons are likely to be used, much less used effectively. Chemical decontamination sites will be established in southern Iraq to scrub tainted vehicles and equipment with a bleach solution. All soldiers involved in the attack will wear protective suits; if exposed and injured, they will be decontaminated before medical evacuation to avoid spreading the chemicals, said another officer.

Gen. Tommy R. Franks, the overall U.S. commander, traveled Wednesday to Saudi Arabia for talks in Riyadh with Crown Prince Abdullah and other senior Saudi officials, Jim Wilkinson, the Central Command spokesman, said from the command's regional headquarters in Qatar. Franks also met with Lt. Gen. T. Michael Moseley, commander of the Air Force deployment at Prince Sultan air base, 60 miles southeast of Riyadh, for discussions about the war plan, Central Command officials said.

Plans have been drafted for military operations nearly two weeks into the ground invasion, according to one senior officer, with various contingencies for capturing Baghdad, its international airport and other high-value targets. Every building in the capital has been numbered by U.S. intelligence for purposes of targeting and to avoid unintended damage.

"But there's no telling which way this is going to go once we get contact with the enemy," the officer said.

Those designated by the Bush administration to be Iraq's postwar architects have set up shop in Kuwait, working out of a beachside resort here. Retired Army Lt. Gen. Jay Garner, the military's director of postwar planning, arrived this week with a large team from the Pentagon. Also returning to Kuwait was Barbara Bodine, the former U.S. ambassador to Yemen who served as charge d'affaires here during the 1990 Iraqi invasion and was stationed in Baghdad in the early 1980s. Officials expect her to return there as the chief U.S. civilian administrator for Baghdad and the surrounding region.

At Camp New Jersey, 31 Air Force weather officers attached to the 101st Airborne Division have begun tracking meteorological conditions in Baghdad and central Iraq, a subject of particular interest to helicopter pilots. But there were preparations also for casualties.

In the 101st alone, more than 550 medical professionals -- including 11 physicians, 25 physician's assistants and hundreds of medics -- have prepared for heavy combat by distributing 6,000 tourniquets and more than 10,000 pressure bandages. Medics have trained on four extraordinarily lifelike mannequins that cost $200,000 each and replicate human trauma symptoms ranging from a fluttering pulse to dilated eyes to massive hemorrhaging; programmed to accept 77 different medications, the dummies "die" if improperly treated.

"Some of these kids are going to see some horrific things," said Lt. Col. R.W. Thomas, 42, the division surgeon. "When they see someone with a smoking stump, we want them to be able to deal with it rather than recoil. The first rule is: Check your own pulse."

Ricks reported from Washington. Staff writer Vernon Loeb in Washington and correspondents Rick Atkinson at Camp New Jersey, William Branigin near the Iraqi border, Susan B. Glasser in Kuwait City and Alan Sipress in Doha, Qatar, contributed to this report.

An explosion is seen in Baghdad early this morning as the United States launched a war on Iraq with cruise missiles and 2,000-pound bombs. Tank crews from the 3rd Infantry Division's Alpha Company, 4th Battalion, 64th Armor Regiment perform a "Seminole Indian war dance" before departing from a Kuwaiti base to a position near the Iraqi border. Military officials have recently described an audacious war plan.