BAGHDAD, Iraq - Separate bombings near an army base and a police building killed at least 28 people and wounded at least 56, Iraqi police said Wednesday.

A bomb in a parked car detonated Tuesday night near an Iraqi army base in Sharqat, about 45 miles from the northern city of Mosul, police said. A suicide bomber detonated his explosives as a crowd gathered at the scene. At least 21 people were killed and 50 wounded, police said.

U.S. soldiers secure the site of a car bomb explosion, in Baghdad, Iraq, Tuesday Sept.19, 2006. A car bomb exploded near a gas station in Baghdad on Tuesday, killing two civilians and wounding another 25, and police recovered the blindfolded bodies of three people from eastern parts of the city. [AP]

A suicide truck bomb slammed into a police headquarters building in Baghdad Wednesday morning, destroying the building and killing seven policemen, police said.

Another six people, including a civilian, were wounded in the attack in the southern Baghdad neighborhood of Dora, said police Capt. Jamil Hussein.

Meanwhile, lawmakers angered by relentless violence in Iraq demanded Tuesday that the defense and interior ministers explain what they are doing to put an end to the death squads that have killed hundreds of Iraqis.

Violence around Iraq killed at least 16 Iraqis on Tuesday, including 10 people killed in a rocket attack on a Shiite neighborhood of Baghdad. An American soldier died in a suicide car bombing in northern Iraq.

Nearly 200 bodies of Iraqis who had been tortured and shot have turned up around Baghdad in the past week, including three found Tuesday in an eastern section of the capital. Most are found bound and blindfolded, apparent victims of sectarian violence.

Both Sunni and Shiite lawmakers called Tuesday for the defense and interior ministers to explain how they plan to stop the killings.

"I demand the defense and interior ministers be summoned to let us know their plans to stop these criminal acts: kidnappings, killings and assassinations against our people," said Hassan Bejar, a lawmaker with the Iraqi Accordance Front, the largest Sunni bloc in government.

Shiite lawmaker Haider al-Safar said: "We are just sitting here and seeing these dead bodies being thrown every day in the streets."

"We need to see real achievements from the defense and interior ministries to stop the daily kidnapping and bloodletting," he said.

Abdul-Karim al-Enizi, another Shiite, proposed special security teams to investigate the killings. There was no immediate response from the ministries.

The U.S. military command, meanwhile, said a soldier was killed Tuesday by a suicide car bomber in northern Iraq. It said another soldier died of non-battle related injuries Monday and two U.S. soldiers were killed Sunday afternoon.

The top U.S. military commander in the Middle East said that because of the increased violence, the U.S. military will likely maintain or possibly even increase the current force levels of more than 140,000 troops in Iraq through next spring.

Gen. John Abizaid, commander of U.S. Central Command, said military leaders would consider adding troops or extending the Iraq deployments of other units if needed.

"If it's necessary to do that because the military situation on the ground requires that, we'll do it," he said. "If we have to call in more forces because it's our military judgment that we need more forces, we'll do it."

The rocket attack in Baghdad's southern Dora district killed 10 people and wounded 19, police said.

In a separate attack, a mortar round hit a house in the Shiite neighborhood of Abu Sayfeen in central Baghdad, killing one person outside the building and wounding three boys, aged between 11 and 15, and their father inside the house, said police 1st Lt. Ahmed Mohammed of the Risafa police station.

About 20 minutes later, another mortar struck near a police checkpoint in Zayouna Street in central Baghdad, killing a policeman and wounding five other people, said police Capt. Mohammed Abdul Ghani.

Earlier, a car bomb exploded near a gas station in Baghdad, killing two civilians and wounding 25.

Elsewhere, gunmen killed Faris Egab, the mayor of Udhaym town, about 40 miles north of the Diyala provincial capital of Baqouba, as he drove to work, the province's police said.

Gunmen also struck in Baqouba, 35 miles northeast of Baghdad, firing on a police patrol near the city prison, killing one policeman and wounding three, the police said.