U.S. Marines backed by Army troops gained a foothold late Tuesday night inside the road that rings the sacred shrine of Imam Ali. The assault seized a multi-story building west of the mosque.

It was the first permanent breach of territory that U.S. forces have opted to take and hold in the neighborhood of winding streets and alleys immediately surrounding the shrine, which Shiite militiamen have been using as a base.

Earlier in the day, Iraqi soldiers backed by U.S. forces began patrolling the streets of Najaf, establishing their presence as part of interim Prime Minister Ayad Allawi's pledge that the new Iraqi army would take the lead in defeating militiamen loyal to a rebellious Shiite cleric.

At the same time, Iraq's interim defense minister, Hazim Shalan, issued a new ultimatum to Sadr and his Mahdi Army militia, warning that the militiamen had "hours to surrender." Shalan had issued similar ultimatums in the past week, but this time his warnings were played over loudspeakers in the area of combat.

In Fallujah, U.S. forces launched an airstrike on an arms cache controlled by foreign insurgents, officials reported. "Based on multiple sources of intelligence, the attack targeted and destroyed a position occupied by numerous foreign terrorists, as well as a weapons cache," according to a U.S. Army statement.

Near Baghdad two Iraqi cabinet ministers survived separate bomb attacks that killed five bodyguards. A car bomb exploded in the southern neighborhood of Qadisiya as the environment minister, Mushkat Mumin, was passing by, officials said. Police said four of her bodyguards were killed, in addition to a suicide bomber, and two people were wounded. Education Minister Sami Mudhaffar survived an attack on his way to work, in the western Baghdad district of Khadra. The blast killed one of Mudhaffar's bodyguards and wounded two others, police said.

An Italian journalist, Enzo Baldoni, who had been taken hostage, was shown in a video on al-Jazeera satellite television on Tuesday. The group that took responsibility for the kidnapping called itself the Islamic Army in Iraq. A spokesman for Italian Prime Minister Silvio Berlusconi said in Rome that the country would not agree to a demand that 3,000 Italian troops be pulled out of Iraq within 48 hours.

"We are committed to obtaining the freedom of Mr. Baldoni, who is in Iraq for private work as a journalist and therefore absolutely not connected to our government," Berlusconi's office said in a statement.

Strong explosions rang through Najaf late Tuesday and U.S. warplanes were heard flying overhead for the third night in a row. Mortar and gunfire echoed in the deserted, battered streets of the Najaf's Old City as units of the Army's 1st Cavalry Division's 7th Regiment pressed toward the road that surrounds the maze of streets and alleys surrounding the shrine.

Overnight, one battalion broke through the road that circles the area of the shrine, covering its advance with tank fire.

"It's tightening the noose, and everybody's doing it," said Maj. Tim Karcher of the 7th Cavalry Regiment, who expressed surprise at the low level of militia resistance to the previous night's attack. "If they don't watch themselves, we'll be in on them in a heartbeat."

"We've closed down to within striking distance," said Lt. Col. Jim Rainey, a military spokesman.

The arrival of Iraqi troops was symbolic in part, but U.S. commanders welcomed the battalion -- several hundred troops -- which they said would help in the labor-intensive business of urban warfare.

Officials said the Iraqi troops would be searching for militia members who might be holed up in houses that have already been checked in the U.S. advance toward the shrine. The Iraqi forces were also expected to help Najaf residents return to their homes mostly in the southwest corner of the old city, now well behind the front lines of the battle.

"We're giving them a little experience and, by the way, letting them bring normalcy to their people," Karcher said.

Iraqi officers described their operations as having a more prominent role than was described by local U.S. commanders.

"We are not supporting the U.S. Army, we are here to evacuate the shrine of the outlaws," said Lt. Haider Hussein, a platoon commander of an Iraqi army anti-riot battalion operating in the area, as is an Iraqi commando battalion training for a possible final assault on the mosque.

"The U.S. Army is supporting us," Hussein said, "because we don't have new weapons to use in this battle."

The current fight for Najaf began Aug. 5, when Sadr's militia ambushed a column of the U.S. Marine force occupying the area. The Mahdi Army, named for a messianic Shiite figure, wields automatic weapons, rocket-propelled grenades and mortars, including devastating 120mm shells.

But the U.S. forces include tanks, infantry fighting armor, 155 mm howitzers, mortars, thermal imaging, radar and digital communications. The ground forces use the communications to call in missile and bomb strikes from a variety of aerial gunships, including the pair of AH-64 Apache attack helicopters that appeared to be flying directly down a Najaf street Tuesday after unleashing two Hellfire missiles.

The streets of the city, usually teeming with pilgrims coming to the shrine to fulfill a lifelong dream, were mostly empty, littered with chunks of concrete and broken glass. Armored Humvees raced along the roads at high speeds to avoid the constant danger of fire, but after 12 days of steady combat, the troops displayed a battle-hardened air of indifference.

"That guy's getting on my nerves," said Spec. Kris Clinkscales of San Antonio, not even looking up when an enemy machine gunner opened up on the wall beside him from the courtyard just across the street.

Clinkscales, one of scores of snipers summoned to the city, where firing precision is crucial, was taking a break from manning a chink in the wall of an unfinished hotel's top story. He had a commanding view of a blackened complex of modern buildings that the 7th Cavalry Regiment had assaulted the night before, just inside the perimeter of the road that rings the shrine.

Off to the right stood the gold dome of the shrine. Commanders and members of the infantry said they understood the importance of keeping it intact.

"You can imagine in America if someone were attacking through Arlington Cemetery for the mall, the amount of consternation," Rainey said.

Patrolling U.S. soldiers run while under fire in Najaf, near a shrine where militiamen continued to take cover.