BAGHDAD -- An insurgent blew up his car yesterday in a central city square yesterday, killing four people. Throughout the country more than 20 Iraqis were killed in a swell of violence, including a blast that killed a police colonel and four children.
Still, with the toll among US service members in the Iraq war approaching 2,000 dead, the US military said it had hampered insurgents' efforts to unleash more devastating suicide bombings, with a series of offensives in western towns.
''We have interrupted the flow of the suicide missions into the large urban areas. Certainly, we have had success denying free movement of car bombs into Baghdad," Brigadier General Donald Alston said in Baghdad.
''It is also a function of Iraqi citizens who have come forward, and with their support we have found car bomb factories. We have found a series of large weapon caches," he said.
In the attack yesterday, the bomber plowed a car laden with explosives into two police vehicles in the central Tahrir Square at 11:30 a.m., killing two police officers and two civilians. US troops rushing to the scene found bystanders tending to 11 wounded.
In the past, Baghdad has been battered by suicide attacks. Almost 700 people were killed from April 1 to early September. The suicide attack yesterday was the deadliest in the capital since a blast on Sept. 26, which killed seven people near the Oil Ministry.
Roadside bombs hit three US convoys in Baghdad yesterday, wounding five soldiers, said a spokesman, US Sergeant 1st Class David Abrams.
The violence followed a week in which 23 US soldiers were reported killed, raising to 1,996 the number of military personnel who have died since March 2003, according to an Associated Press count.
Also yesterday, a suicide car bomber rammed into a US military convoy in the northern city of Kirkuk. Two civilians were killed; 13 were wounded.
Attacks also flared in north-central Iraq. The police colonel and his children were killed in Tikrit, north of Baghdad.
Lieutenant Colonel Haitham Akram had left his home and was getting into his car with his two sons when a bomb went off, killing the three of them, officials said. The explosion set a nearby car ablaze, killing two girls, ages 7 and 9.
In another development yesterday, judges took testimony from the first witness in the mass murder trial of Saddam Hussein and seven aides over the 1982 massacre of 148 Shi'ites in Dujail.
The judges went to a military hospital to take the deposition from Wadah Ismail al-Sheik, a cancer patient who was director of the investigation department at Hussein's Mukhabarat intelligence agency at the time of the Dujail massacre. Sheik was too sick to appear in court, and officials did not want to wait for a resumption of the trial, scheduled for Nov. 28, to get his testimony.
In addition yesterday, the US military confirmed that four American contract workers had been killed and two had been wounded in Iraq last month, when their convoy got lost.
They died in an attack on Sept. 20, when the convoy, which included US military guards, made a wrong turn.
They headed into the mostly Sunni Arab town of Duluiyah, about 45 miles north of Baghdad. Insurgents opened fire with rifles and rocket-propelled grenades, said Major Richard Goldenberg, a spokesman in north-central Iraq.
Alerted to the attack, a team went to the scene, finding all four Americans still in their vehicles with bullet wounds, one of them burned from a fire in the vehicle. One was still alive but died later of his wounds, the military said. Two others were wounded and survived the attack.
Three of the dead worked for