Iraq Vice President Taha Yassin Ramadan says thousands of Muslims who say they are ready for martyrdom have flocked to Iraq since the U.S.-led war began.
Earlier this month, Iraqi officials took foreign journalists to a training camp east of Baghdad to show off about 40 of what it said were volunteers from Algeria, Libya, Tunisia, Egypt, Syria and Saudi Arabia.
On Saturday, a bomber posing as a taxi driver summoned American troops for help at a checkpoint north of Najaf, then blew up his vehicle, killing himself and four soldiers.
The suicide bombing was the first against U.S. and British forces since the invasion began.
"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 Baghdad news conference. "This is just the beginning. You'll hear more pleasant news later."
Iraq's state television reported that the bomber — identified as Ali Jaafar al-Noamani, a noncommissioned officer with several children — was posthumously promoted to colonel and awarded two medals by Saddam Hussein. His family reportedly was awarded 100 million dinars — the equivalent of $34,000, a fortune in Iraq.
President Bush, speaking before a meeting with his war council, said, "We are now fighting the most desperate units of the dictator's army."
Joint Chiefs of Staff Chairman Gen. Richard Myers, in an interview Sunday with the BBC, said, "I would think the toughest fighting is ahead of us."
In other major developments:
In central Iraq, thousands of Marines pushed north Sunday in "seek and destroy" missions, trying to clear the route toward Baghdad that they have nicknamed "Ambush Alley." Marine infantry and tank units moved into previously unsecured areas, seeking to provoke attacks in order to locate Iraqi fighters.
U.S. and British warplanes launched bombing raids early Sunday near Karbala, south of Baghdad, targeting Iraqi fuel storage depots. Wing Commander Andy Suddards, who led a British Harrier raid on one of the depots, said one goal was to cut the fuel supply chain for Republican Guard tanks. "The visibility was good and I saw the bang," Suddards said. "If the tanks have no fuel, it is all going to help."
U.S. warplanes attacked Baghdad's defenders with bombs and strafing fire Sunday. Three-quarters of the allied airstrikes are now going after Republican Guard forces ringing Baghdad, says Air Force Brig. Gen. Daniel Darnell. The U.S. Central Command said Sunday that the latest targets in Baghdad hit by coalition aircraft included military facilities at the Abu Garayb Presidential Palace, the Karada military intelligence complex and the barracks of a major paramilitary training center. Several telephone exchanges in the city also were hit, as well as a train loaded with Republican Guard tanks.
U.S. aircraft flew combat missions from Iraqi soil for the first time Saturday, when A-10 warplanes flew out of a captured Iraqi base south of Baghdad to conduct strikes.
Group Capt. Al Lockwood, a British spokesman, said the Iraqi general was captured in the besieged city of Basra. "We'll be asking him quite politely if he's willing assist us to continue our operations against the paramilitary forces in Basra," Lockwood said of the highest-ranking Iraqi prisoner of war thus far. Lockwood also said Royal Marine Commandos killed a Republican Guard colonel who apparently was sent to Basra to strengthen the resolve of the defense forces, who are encircled by British troops. On Saturday, British troops darted in and out of the southern city, destroying five Iraqi tanks and two statues of Saddam Hussein. About 1,000 Saddam loyalists are holed up in Basra, where essential supplies are running low and Iraqi fighters have kept residents from leaving, British officials say.
Anti-Saddam Kurdish militiamen moved on two fronts in northern Iraq on Saturday, joining U.S. special forces in an attack on Islamic militants and advancing unopposed closer to the government-held city of Kirkuk and its oil fields.
The U.S. Central Command said Saturday it was trying to determine if nine Marines who died the previous weekend near an-Nasiriyah as Iraqis were surrendering were killed by Iraqi or American fire. The Washington Post on Friday quoted a military source as saying an A-10 Thunderbolt II warplane may have mistaken the Marines for Iraqi fighters and attacked them. Army Lt. Gen. John Abizaid said last week that the Marines were ambushed March 23 after Iraqi solders faked a surrender then fired a rocket-propelled grenade.
U.S. Central Command on Sunday announced the deaths of two Marines in separate Humvee accidents in South-Central Iraq. One died late Friday when he was struck by a Humvee during a firefight with Iraqi soldiers; the other drowned on Saturday when his vehicle rolled into a canal.
Two Newsday journalists who disappeared from Baghdad may have been detained by Iraq's government, according to the editor of the Long Island, New York newspaper.