Meanwhile, an Iraqi official said 4,000 Arab volunteers have arrived, eager to carry out more suicide attacks against U.S. and British forces.
On Saturday, four American infantrymen were killed in a suicide bomb attack in Iraq.
Gen. Tommy Franks, commander of the allied coalition, denied at a briefing Sunday that he had asked the Pentagon for more troops before invading Iraq. He sidestepped a question about whether the war might last into the summer.
Franks was responding to published reports that the requests of U.S. generals for more ground troops were repeatedly denied by Defense Secretary Donald H. Rumsfeld. Reports also quoted U.S. military officials as saying the lack of troops and weapons meant the war might last into the summer.
"One never knows how long a war will take," Franks said.
In other major developments:
The Iraqi general was captured in the besieged city of Basra, Group Capt. Al Lockwood, a British spokesman, said. He is the highest-ranking Iraqi prisoner of war thus far.
"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.
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.
Further north, along the approach routes to Baghdad, some American units have paused while supply lines are shored up, but others were engaged in battles to clear the way for an all-out assault. U.S. and British warplanes have focused three-quarters of their strikes in recent days on Republican Guard positions defending the capital.
Although coalition commanders have been unflaggingly upbeat about the progress of the war, American soldiers in the field were jolted by news a car bombing Saturday in which an Iraqi soldier posing as a taxi driver gestured for help at a checkpoint near the city of Najaf, then blew up his car as soldiers approached. Four Americans from the Army's 1st Brigade, 3rd Infantry Division were killed; their names were not immediately released.
"It's a shame they are doing that, because now we're going to have to treat every civilian vehicle like it is hostile," said Staff Sgt. Bryce Ivings of Sarasota, Fla., a member of 3rd Battalion, 7th Infantry Regiment.
Iraqi Information Minister Mohammed Saeed al-Sahhaf contended at a briefing Sunday that several Iraqi civilians had been shot dead in their cars by coalition soldiers in a mood for vengeance after the suicide attack.
Lt. Gen. Hazem al-Rawi, a senior Iraqi defense official, said the suicide attack marked "the beginning of a long path of jihad for Iraqis and Arabs against the invaders." More than 4,000 volunteers have come from numerous Arab countries to participate in suicide attacks, he said.
Iraq's state television reported that the Najaf 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.
Iraq's vice president, Taha Yassin Ramadan, indicated the attack was part of a coordinated effort to thwart the invasion force, and he raised the specter of terrorism on U.S. or British soil.
"The day will come when a single martyrdom operation will kill 5,000 enemies," Ramadan said. "We will use any means to kill our enemy in our land and we will follow the enemy into its land. This is just the beginning."
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."
U.S. and British warplanes launched bombing raids early Sunday near Karbala, south of Baghdad, targeting Iraqi fuel storage depots.
Like Franks, Rumsfeld too denied published reports that he had rejected requests from U.S. war planners for additional troops.
"The planners are in the Central Command. They come up with their proposals and I think you'll find that if you ask anyone who's been involved in the process from the central command that every single thing they've requested has in fact happened," Rumsfeld said in a broadcast interview.
The plan developed by Franks is "a good one and it's working. I think the people who are talking about it really are people who haven't seen it," the defense secretary said.
Rumsfeld would not say when the fighting might cease.
"We've never had a timetable. We've always said it could be days, weeks or months and we don't know. And I don't think you need a timetable," Rumsfeld said in a broadcast interview.
He also took on critics of the war strategy who contend the United States underestimated Iraqi resistance.
"It's been going on nine days. It's a little early for post-mortems," Rumsfeld said.