Allied bombers focused attacks on Iraqi ground forces and equipment in and around Kuwait yesterday, and U.S. officials said a series of overnight raids on Iraqi patrol boats had virtually eliminated any remaining threat from the small Iraqi navy.

With ground activity near the Saudi-Kuwaiti border described by military briefers as relatively quiet yesterday, allied aircraft pounded "targets of opportunity" inside Kuwait, while maintaining their continual assault on the elite Republican Guard forces in southern Iraq. Officials said one wave of B-52 bombers "scattered" about 300 Republican Guard vehicles, which were then attacked by waiting aircraft, resulting in "fairly substantial kills" of tanks and armored personnel carriers.

U.S. officials said Iraqi forces inside Kuwait appeared to have gone back into defensive positions with only sporadic fighting along the border in the wake of their unsuccessful attack on the Saudi Arabian city of Khafji earlier in the week. But U.S. planes continued to assault the Iraqi positions in a systematic air campaign designed to soften up the Iraqi forces in preparation for a possible ground war later.

"We feel confident we can focus on the KTO {Kuwaiti Theater of Operations}, having achieved the kind of destruction on the strategic targets that we talked about during" the first phases of the air campaign, Marine Maj. Gen. Robert B. Johnston, chief of staff of the U.S. Central Command, said yesterday.

Johnston also reported that one Marine was killed and two were wounded early yesterday in a cluster bomb attack that appeared to be the result of friendly fire. Officials said the location of the incident -- well back from the Saudi border -- appeared to rule out hostile fire, although they were still looking into the attack. The U.S. military is also investigating the deaths of 11 Marines earlier in the week to determine whether they were killed by friendly fire.

Two U.S. planes -- an A-10 Thunderbolt II tank-killing aircraft and an A-6 Intruder fighter-bomber -- were shot down yesterday by Iraqi antiaircraft fire. U.S. officials declined to specify where the planes had gone down and said they had launched search-and-rescue missions for the downed fliers. That brought the number of allied aircraft downed since the war began to 22, 15 of them U.S. planes and seven from other countries in the allied coalition.

Iraq fired at least three more Scud missiles yesterday, two at Israel and at least one at Riyadh in Saudi Arabia. Both Scuds aimed at Israel apparently landed in remote, uninhabited areas of the Israeli-occupied West Bank. The Israeli military command reported there were no injuries or damage from the missiles. The Scud lobbed at Riyadh was destroyed by a U.S. Patriot missile, but debris from it landed in a residential area and slightly injured 29 people, a Saudi Interior Ministry official said.

Despite yesterday's attacks, U.S. officials said they believed the intensive Scud hunt had borne fruit. They noted that the Iraqis had launched 35 Scuds during the first week of the war, 18 during the second week and only a handful so far this week. "We think we see a downward trend," said Lt. Gen. Thomas Kelly, senior operations officer for the Joint Chiefs of Staff. Allied military officials said U.S. planes had destroyed three vehicles at a Scud missile site on Friday night.

Saudi officials reported that the large oil slick created when Iraq dumped oil into the gulf last week reached the Saudi coastline, polluting beaches and washing dead birds onto the shore. But the winds appeared to have slowed the movement of the slick to the south, giving officials more time to protect a crucial water purification plant in the industrial city of Jubail as well as two islands that are breeding grounds for the endangered sea turtle.

The overnight raids on Iraqi patrol boats helped ease fears among U.S. officials that the Iraqi navy, although small in numbers, could threaten U.S. ships in the northern Persian Gulf with highly accurate, French-made Exocet missiles. The Iraqis used an Exocet to hit the USS Stark in May 1987, killing 37.

Johnston described the Iraqi navy as "combat ineffective" after four naval engagements Friday night and yesterday in which U.S. planes knocked out several patrol boats that were capable of launching the Exocets. Allied forces systematically sought out Iraqi naval vessels, which Johnston said were trying to hide out in the northern gulf. Some captured Iraqi prisoners reported they were trying to seek shelter in Iranian waters, but officials said none appeared to have been successful.

"The Iraqi air force is totally ineffective, the Iraqi navy is totally ineffective, so two of {Iraqi President Saddam Hussein's} three pillars are not effective and we are concentrating on the third," Kelly said.

For the first time since the outbreak of the war, elements of the 82nd Airborne Division were drawn into the fighting, a brief skirmish about 10 miles inside of Saudi Arabia. There were no casualties reported in the Friday night clash. Qatari forces also engaged Iraqi troops briefly near the border, destroying four Iraqi tanks and damaging a fifth.

But U.S. officials said the border area was generally quiet after the intensive fighting earlier in the week. "There's been very little ground activity around the border," Johnston said. "There is no indication of any substantial gathering of units that would reflect any kind of offensive initiative on the part of the Iraqi forces."

Johnston said that when allied forces detected movement north of the border, they were attacking the Iraqis from the air. "We're now focusing on isolating the KTO," he said, adding that there were more "targets of opportunity" than in the past.

Although the focus of the air campaign has shifted, allied aircraft continued to hit targets inside Iraq. British Group Capt. Niall Irving reported that British aircraft had inflicted "devastating" damage on two Iraqi airfields.

Irving also said British aircraft were engaged in intensive support of logistical activities to support the buildup of ground forces.

Defense Secretary Richard B. Cheney, interviewed on Cable News Network yesterday, reiterated the allied view that despite the ground combat earlier in the week, Saddam would not be allowed to determine the timing of an all-out ground war. "We're not going to do that until we're ready," Cheney said.

President Bush called on Americans to make Sunday a day of prayer "for the safety of the troops, these men and women who have put their lives and dreams on hold because they understand the threat our world faces." In a midday radio address, the president said the United States is at war "against the oldest enemy of the human spirit, evil that threatens world peace."

Pope John Paul II criticized the "unbelievable violence and useless slaughter" of the war and called for a peaceful resolution. "We can't lose the hope that the great suffering that is striking such vast portions of humanity ends as soon as possible," the Roman Catholic leader said in remarks that Vatican Radio said were broadcast in Europe, Africa and the Middle East.

There was more bellicose rhetoric from Iraq yesterday, with the defense ministry's newspaper threatening that Iraqi forces would use every weapon available against the allied coalition.

"The Iraq leadership and people will not give up their country, and we will use whatever power and weapons are at our disposal, starting from kitchen knives to weapons of mass destruction," the newspaper Al-Qaddisiya said in a front-page editorial.

The newspaper also warned that the allies will have "no choice but to fight a ground war" that will turn the battlefield into "a place for a real massacre, and we will not give them the opportunity to remove their dead from the pools of blood in which they will float."

A military communique accused the allied forces of "cowardice" in refusing to be drawn into the ground war at this time. Saying the allies are relying on bombers at high altitude, the communique went on to say the allies "do not dare to approach within the range of our valiantly manned air defenses."

Iraq's Deputy Prime Minister Saadoun Hammadi yesterday concluded a visit to Tehran, where he failed to obtain release of Iraqi aircraft that have flown to Iran since the outbreak of the gulf war. Iranian leaders reportedly told the Iraqi official that the planes would remain in Iran until the war ends.

Hammadi was given a message from Iranian President Ali Akbar Hashemi Rafsanjani to Saddam. The Iranian news agency IRNA said Rafsanjani had told Hammadi, "The only solution to the war is an Iraqi withdrawal from Kuwait and the withdrawal of all foreign forces from the region."

Jordan responded to U.S. criticism that its importation of Iraqi oil is violating United Nations economic sanctions.

"Anyone who is slightly familiar with the law will know that there is nothing that requires a state in applying a legal obligation such as sanctions to commit economic suicide," said Aoun Khasawneh, a legal adviser to the Jordanian royal family. He added that unless other nations can guarantee supplies of oil from elsewhere, Jordan will continue to use Iraqi oil.

U.S. officials said they were monitoring a second oil slick in the northern Persian Gulf caused by leakage from the Mina al Bakr oil terminal off the Iraqi coast. They said the slick, estimated at 40 miles long by six or seven miles wide, did not appear to be a deliberate Iraqi release of oil into the gulf and may have resulted from hostilies in the area.

Saudi officials continued their efforts to block the larger oil slick that was set off by Iraqi sabotage from damaging key facilities along the Saudi coast. Abdullah Dabbagh, president of the Research Institute of King Fahd University of Petroleum and Minerals, and a key government adviser, told reporters here that the turbulent winds were mostly "good news" because they will allow officials to set up additional diversionary booms and other equipment to protect the water desalination plant in Jubail.

The winds "give us some breathing time" of another few days before the slick reaches Jubail, he said. But he acknowledged that the Saudis were "very short" of equipment to protect key facilities.

The slick, now stretching over more than 50 miles of the Persian Gulf, is estimated by U.S. officials to contain between 7 million and 12 million barrels of oil. The existence of the main slick was disclosed on Jan. 25 when U.S. military officials in Riyadh charged that Iraq had uncapped the pipelines of the Sea Island Terminal about 10 miles off the coast of the Kuwait. The next night, the U.S. Air Force bombed the piping system of the terminal, cutting off the flow of oil into the gulf and stopping the growth of the slick.

But Jerry Gaines, economic officer to the U.S. Embassy in Riyadh, said chemical tests performed by Saudi Aramco last Wednesday on samples from the southern portion of the main slick showed conclusively that the oil had been at sea for at least 11 days and came from oil wells in Iraq, not Kuwait. He said this means that the slick began not with the oil uncapped from the Sea Island Terminal, but from five tankers that were loaded with Iraqi crude and dumped into the Persian Gulf starting around Jan. 19, a few days after the war began.

Gaines said U.S. officials viewed the tests as further evidence that Iraq had intended from the beginning to use the dumping of oil into the gulf as a weapon of war.

Staff writers R. Jeffrey Smith in Washington, William Claiborne and Jackson Diehl in Israel and Edward Cody and Michael Isikoff in Saudi Arabia and staff researcher Lucy Shackelford contributed to this report.