At the airport, American tanks were reported to have broken through the walls that ring Saddam International Airport on the western side of the city. Fighting was described as fierce.

The Army's Third Division was approaching the city from the southwest, while the First Marine Division pressed toward Baghdad's suburbs from the southeast. The marines were 25 miles from the outskirts tonight.

"A vise is closing," President Bush told marines during a visit to Camp Lejeune, N.C., today. "Our destination is Baghdad, and we will accept nothing less than complete and final victory."

Iraqi officials were silent on the lack of power in Baghdad, a city of five million, and the United States Central Command, which is overseeing the military campaign against the Hussein government, denied that it had made the city's power grid a target.

With the airport attack under way, Defense Secretary Donald H. Rumsfeld called on senior officers of Iraq's armed forces to give themselves up. "For the senior leadership, there is no way out," he said at a Pentagon briefing in Washington. "Their fate has been sealed by their actions."

The advance toward Baghdad followed breakthroughs for American and British troops across the country. American officials were especially heartened by reports that a top Shiite cleric in Iraq had issued a fatwa, or religious decree, supporting the coalition invasion.

In southern Iraq, British forces moved into the city of Basra, and American marines surrounded the important city of Kut. United States officials said special forces had been active in and around Baghdad early today, checking bridges and other key structures for explosives.

But it remained uncertain what had happened to Baghdad's main defenders, the Republican Guard, six divisions of more than 10,000 troops each.

The Republican Guard was variously reported to have regrouped dispersed or "melted away." On Wednesday, the United States military said two Guard divisions had been rendered ineffective after two weeks of bombardment.

That assertion jibed with observations from reporters accompanying coalition forces who said the advance around Baghdad had met only sporadic resistance.

Reporters traveling with troops toward Baghdad saw dozens of Iraqis taken prisoner along the roadside. But those reports of prisoners would not account for more than a fraction of Guard troops.

Asked about the Republican Guard's whereabouts, Brig. Gen. Vincent Brooks said at a briefing at Central Command's forward headquarters in Qatar that "there is some movement that's ongoing," but he added that he did not know whether troops were "melting away" or "repositioning."

The British defense secretary, Geoff Hoon, said in Parliament today that 9,000 Iraqis -- less than the number of troops in one division -- had been taken prisoner during two weeks of war.

Officials at Central Command, speaking on condition of anonymity, told reporters that several Republican Guard units based north of the capital were moving south. It was unclear if that meant they were cutting through the heart of the city.

Last week, the vice director of operations for the Joint Chiefs of Staff, Maj. Gen. Stanley A. McChrystal, described Iraq's Medina Division, based north of Karbala, as the "linchpin" and "one of the most powerful" divisions of the Republican Guard. On Wednesday, General McChrystal said the Medina was one of two Republican Guard divisions no longer considered "credible" fighting forces.

Wary of the possibility of military coups, Mr. Hussein has had a policy of not allowing the Republican Guard into the city. Top Republican Guard officers were reportedly involved in at least one attempted coup in the 1990's.

Several overlapping security organizations are believed to police and protect the capital, including a Special Republican Guard of 10,000 soldiers and other security organizations and secret police forces.

The Iraqi government remained defiant today even with coalition troops at its doorstep. As a column of more than 1,000 vehicles reached the suburbs of Baghdad, Iraq's information minister, Muhammad Said al-Sahhaf, convened his daily press conference in a scene of almost surreal calm and denial.

United States troops were "not even 100 miles" from Baghdad, he said. When told by a reporter that news reports said American forces were just outside the airport, he smiled and responded sarcastically, "If that's the case, we'll go and welcome them with flowers and music."

Mr. Sahhaf said United States and British troops held no territory in Iraq. "They are a snake moving in the desert," he said.

He offered a litany of Iraqi military successes that stood in stark contrast with reports from American officers and journalists traveling with them.

United States marines had been "defeated, beaten bitterly" at Kut, he said. "We are giving them the real lesson today," he said. "We are destroying tanks, personnel carriers and we are killing them."

In Qatar, Central Command said special forces troops in Iraq had "very good freedom of action," in General Brooks's words, and were in control of the highway from Baghdad to Tikrit, Mr. Hussein's hometown.

General Brooks showed nighttime video of special operations forces raiding a palace used by Mr. Hussein and his sons near Baghdad. He said the troops had not found any of the regime's leaders but did find a large number of documents.

In Najaf, the United States appeared to gain key support from a Shiite Muslim leader who issued a decree urging Iraqis not to hinder the invasion. The fatwa was reported by General Brooks at his briefing and confirmed by a Shiite group in London, the Al Khoei foundation.

The fatwa was attributed to Grand Ayatollah Ali Sistani, the leader of a theological school in Najaf, who has been under house arrest since a failed Shiite uprising in the south following the 1991 Gulf War. Ayatollah Sistani is one of the most prominent authorities in Shiite Islam and thus one of the most influential religious leaders in Iraq, which has a Shiite majority. Saddam Hussein is a member of Iraq's Sunni Muslim minority.

"A prominent cleric, Grand Ayatollah Sistani, who had been placed under house arrest by the regime for a considerable period of time, issued a fatwa," General Brooks said in Qatar.

It was a rare moment of support for the United States invasion by a Muslim cleric amid widespread protests against the United States in nearly every Muslim country in the Middle East and Asia. General Brooks called it a "turning point."

"And it was done this morning, instructing the population to remain calm and to not interfere with coalition actions," the general said. "We believe this is a very significant turning point and another indicator that the Iraqi regime is approaching its end."

But news of the fatwa was mitigated by television images from Najaf showing United States troops retreating before a crowd of angry residents. The crowd blocked the passage of troops toward the gold-domed Ali Mosque, which is revered by Shiites and contains the tomb of Imam Ali bin Abi Talib, the cousin and son-in-law of the Prophet Muhammad.

"City, yes! Ali Mosque, no!" one resident yelled.

On Wednesday, United States troops were greeted with cheers by hundreds of well-wishers, a rare welcome in a war that has seen United States and British troops met with ambivalence.

In Basra, more than a week after British forces surrounded the city, troops cautiously moved into an industrial area on the edge of the city. Iraq denied that any incursion had been made. "This is completely untrue," said Mr. Sahhaf, the information minister. "Basra is in good shape. She is strong."

Reporters traveling with the troops said the British had advanced less than a mile from the south toward the city center and were met by Iraqi forces using rocket-propelled grenades, machine-guns and a T-55 tank.

Lt. Col. David Paterson said troops had established a checkpoint in the industrial area to "poke a toe into Basra to see what happens."

"The purpose is to get information from the civilians going in and out of the city about what is happening right inside," he said.

(China Daily April 4, 2003)