Kuwait City ? As squadrons of American and British warplanes pounded Iraqi defenses around Baghdad, a suicide bomber detonated an explosives-laden taxi Saturday at a U.S. checkpoint near the contested city of Najaf, killing four U.S. soldiers in the first such attack of the war.

U.S. officials branded the blast as terrorism. President Saddam Hussein’s government awarded the bomber two posthumous medals and Taha Yassin Ramadan, the Iraqi vice president, warned that suicide attacks would become “routine military policy” in Iraq and the United States unless the Bush administration abandons the 11-day-old war and pulls back its troops.

The attack occurred shortly before 11 a.m. (2 a.m. CST) when a taxi driven by a man identified by Iraqi officials as a noncommissioned military officer named Ali Jaafar al-Nuamani stopped near a highway roadblock manned by soldiers from the 1st Brigade of the U.S. Army’s 3rd Infantry Division, U.S. military officials said. The driver waved for help, indicating his car was broken, but when soldiers approached the vehicle, it exploded, the officials said.

The bombing was the most devastating example of the unconventional tactics Saddam’s loyalists have employed to harass U.S. and British ground forces along a 250-mile line stretching from the Kuwaiti border to the city of Karbala 50 miles south of Baghdad. Such bombings present a new challenge for U.S. commanders as they seek to protect their troops and secure supply lines but also to deal with Iraqi civilians in a way that persuades them the U.S.-British assault on Saddam’s government can be to their benefit.

Since the war began March 20, paramilitary groups have mounted a relentless guerrilla resistance against coalition troops, staging ambushes and hit-and-run attacks along the lengthy supply columns, particularly at the cities of Najaf and An Nasiriyah near the Euphrates River.

Officers and war planners have huddled in recent days to craft a new approach that will focus more on smashing Saddam’s paramilitary organizations than on waiting until Baghdad falls to clean up pockets of resistance in the rear.

U.S. commanders have decided to seek advice from British colleagues who have urban warfare experience and have staged commando raids and abductions aimed at decapitating the leadership of Saddam’s Baath Party and its paramilitary units in southeastern Iraq. U.S. commanders also have opted to deploy thousands more Marines to protect vital roads and flush out militiamen from strategic intersections.

Marine reinforcements

In the first significant addition to coalition forces since the war began, 2,300 Marines from the 24th Marine Expeditionary Unit landed Saturday in Kuwait and quickly will deploy to the sites in southern Iraq where resistance has been fiercest.

In the past few days, the U.S. military has focused much of its counterinsurgency activity in and around An Nasiriyah, a city of about 500,000 people about a third of the 300-mile distance between the Kuwaiti border and Baghdad. Although Marines seized two bridges there last weekend that are crucial to the movement of troops and supplies toward Baghdad, U.S. supply convoys have been subjected to regular attacks from a paramilitary group called Saddam’s Fedayeen.

Marines attempting to create a wider security buffer around the bridges fought gun battles with Iraqi solders and militiamen Saturday, U.S. officials said. Marines have turned up several shallow graves around the city over the past two days and they were trying to determine whether the bodies were those of U.S. troops who have gone missing in a week of sporadic clashes.

Coalition warplanes bombed a meeting hall near the southern port city of Basra where intelligence reports said 200 members of the Baath Party were meeting, U.S. military officials said.

The suicide bombing occurred near Najaf, a dusty, downtrodden city about 90 miles south of Baghdad that is home to the holiest shrine in the Shiite branch of Islam — the tomb of Ali, son-in-law of the prophet Mohammed — and is a renowned center of Shiite learning.

Much of the 3rd Infantry Division has assembled between Najaf and Karbala as it prepares to confront the Medina division of Saddam’s elite Republican Guard before making a final thrust into the capital. Although the 3rd Infantry has been trying to rest and resupply after a high-speed dash through the desert from Kuwait, many of its units have been tied up trying to target militiamen in and around the two cities.

‘Rule to terror’

In his weekly radio address, President Bush said Saddam had been reduced to “rule by terror,” suggesting the resistance encountered by U.S. troops was forced. Bush mentioned, as did his military spokesmen, a report that an Iraqi woman who waved to U.S. or British troops earlier this week was found hanging from a street lamp when the soldiers returned.

“We are now fighting the most desperate units of the dictator’s army,” Bush said. “The fighting is fierce, and we do not know its duration. Yet we know the outcome of this battle: The Iraqi regime will be disarmed and removed from power. Iraq will be free.”

Commenting on the suicide bombing, Ramadan said the Iraqi government will stage more such attacks against the invading forces. In military parades before the war scores of young Iraqi men paraded in the same white shrouds worn by aspiring Palestinian suicide bombers in the West Bank or Gaza Strip. Arab media and Iraqi dissidents have reported that Saddam established a training camp for Arabs who volunteered to carry out suicide attacks.

“We will use any means to kill our enemy in our land and we will follow the enemy into its land,” Ramadan said at a news conference in Baghdad. “This is just the beginning. You’ll hear more pleasant news later.”

He said Iraq would use suicide and guerrilla tactics to compensate for its technological disadvantage in weaponry. “They have bombs that can kill 500 people, but I am sure that the day will come when a single martyrdom operation will kill 5,000 enemies,” he said.

Air Force Maj. Gen. Victor E. Renuart Jr., the U.S. Central Command’s director of operations, called the suicide attack “a symbol of an organization that’s starting to get a little bit desperate.” At a Pentagon news conference, Maj. Gen. Stanley McChrystal, vice director of operations for the Joint Chiefs of Staff, said suicide attacks would lead to greater vigilance by American troops but would not fundamentally change the way U.S.-led forces proceed in the war.

“We will treat vehicles differently now,” said First Sgt. Chris French, 39, of Richmond Hill, Ga., assigned to Bravo Company, 3rd Battalion, 15th Regiment in the 3rd Infantry Division’s 2nd Brigade. “We’re basically not going to get near them unless we can see some skin and they’re not hiding anything.”

Although officials at the Pentagon and the Central Command’s field headquarters in Qatar publicly dismissed the significance of the suicide bombing, several privately voiced concern that the attack would have an impact, especially on humanitarian relief that requires interaction with civilians. They expressed fear that such tactics could challenge a U.S.-led occupation force, despite Defense Secretary Donald Rumsfeld’s contention that intense defiance likely will disappear when Saddam and his Baath government fall.

The four killings, along with the disappearance of a Marine in An Nasiriyah, brought to 42 the number of killed or missing U.S. troops since the conflict began. Pentagon tallies, however, have often lagged as reports work their way through the bureaucracy and families are notified.

Bombs on Baghdad

News of the suicide bombing seemed to buoy Iraqi officials, who have become more strident in recent days over a relentless, around-the-clock U.S. air campaign that has targeted government communication facilities, presidential palaces and some ministries. By nightfall, thunderous explosions reverberated over the capital, with the most intense barrages apparently targeting military positions on the outskirts.

In a pre-dawn attack, Iraq’s Information Ministry was damaged, but the building remained intact. From the vantage point of the street, little destruction was visible from a missile that appeared to have penetrated the roof of the 11-story building. Ministry officials said the 10th floor, which houses an Internet server, was gutted, and some satellite dishes were destroyed.

Information Minister Mohammed Saeed Sahhaf said 68 civilians were killed and 107 wounded over the past 24-hour stretch. Shuala, a working-class Shiite Muslim neighborhood, witnessed the greatest carnage when a blast ripped through a crowded market. Iraqi officials said 58 people were killed; hospital personnel said the death toll rose to 62 overnight.

While U.S. forces did not move their front lines, they continued to pound Republican Guard divisions from the air, taking advantage of the clear weather to whittle away at defensive positions south of Baghdad before any ground assault. AH-64 Apache attack helicopters struck at the Medina division, destroying several tanks, armored personnel carriers, artillery pieces, multi-purpose vehicles and radar for surface-to-air missiles, Renuart said.

Army Brig. Gen. Vincent Brooks, briefing reporters in Doha, said U.S. Army Rangers carried out a successful raid on an Iraqi headquarters that controlled most commando operations in the country’s western desert. He said the U.S. forces captured 50 Iraqis as well as ammunition, gas masks and radios.

A defense official said elements of the 82nd Airborne Division seized a significant airfield “in the last couple of days” about 150 miles from the Kuwaiti border in southeastern Iraq. The airstrip is intended to serve as a forward base for attack planes, such as the A-10 Thunderbolt II, to fly close air support for ground troops.

Iraqi forces staged their own raid overnight at the Basra International Airport, sending in a contingent of light armored vehicles in what the British officers saw as an attempt to probe defenses. The British reported driving off the attack, destroying three Iraqi tanks with artillery or anti-tank weapons and calling in U.S. AH-1 Cobra attack helicopters which reported hitting another two tanks.