BAGHDAD - Car bombs killed 30 people in Iraq on Sunday and wounded more than 70 in one of the bloodiest spasms of violence of recent weeks as political leaders closed in on a deal to form a national unity government.

The southern city of Basra was largely calm as British military engineers examined the wreck of a helicopter whose apparent shooting down was followed by clashes between troops and youths chanting triumphal Shi'ite militia slogans.

Iraqis stand outside a house damaged by a rocket attack in Baghdad May 6, 2006. Two children ages 5 and 6 were killed and three adult civilians were wounded when a mortar round landed on Baghdad's western district of Shula on Saturday, police said. [Reuters]

Twenty-one people were killed and 52 wounded when a car bomb went off close to the main central bus station in the Shi'ite holy city of Kerbala, 110 km (70 miles) south of Baghdad, police said. Around the same time, two cars exploded in the capital.

A suicide car bomber hit an Iraqi army patrol in the mainly Sunni northern district of Aadhamiya, killing eight people and wounding 15. Soldiers and civilians were among the casualties.

Iraqi and U.S. forces conducted a sweep for rebels in Aadhamiya on Saturday, the U.S. military said. The area is a stronghold of Sunni Arab insurgents.

A second car bomb exploded at a busy traffic intersection in northern Baghdad, killing one civilian and wounding five. The target was not clear.

Interior Ministry sources said 42 bodies had been found in the last 24 hours in the capital alone, including eight found dumped near Kindi hospital in central Baghdad. The figure is in line with levels of violence seen in recent months.

Sectarian violence sparked by the February 22 bombing of a major Shi'ite shrine in Samarra has led to the discoveries of bodies -- many showing signs of torture -- on a frequent basis.

Sunni leaders blame pro-government Shi'ite militias and the Shi'ite-dominated police for some of the killing. Militia leaders speak of a need to respond to three years of violence by insurgents from the once dominant Sunni minority.

Sectarian bloodshed has prompted warnings Iraq is sliding toward civil war and added urgency to efforts by political leaders to form a unity government that can reverse the trend.

GOVERNMENT TALKS

Nuri al-Maliki, the Shi'ite Islamist nominated as prime minister two weeks ago after months of stalemate following a December election, says he expects to name a cabinet shortly.

Representatives of the majority Shi'ites, Kurds, Sunnis and others were meeting again on Sunday. On Saturday, the Shi'ite vice president said he expected a deal "in the next few days."

The U.S. military said last week that Sunni Islamist hardliners around al Qaeda figurehead Abu Musab al-Zarqawi were stepping up violence around Baghdad, aimed at derailing the efforts to forge a consensus government.

Zarqawi has in the past declared war on Shi'ites, who were oppressed under Saddam Hussein. Attacks in Kerbala and other Shi'ite centers have been characterized by some Iraqi leaders as attempts to provoke Shi'ite militias into all-out warfare.

Youths chanting slogans in favor of the Mehdi Army militia of anti-occupation Shi'ite cleric Moqtada al-Sadr threw rocks and petrol bombs at British troops cordoning of the crash site in Basra on Saturday where the military helicopter came down.

After a curfew and with a heavy presence of Iraqi police and troops, Iraq's southern second city was calmer on Sunday after the violence in which a health official said five Iraqis died.

Several British troops were killed in the helicopter. Iraqi firefighters reported finding four bodies. The British forces declined to say how many died or describe the aircraft or how it came down on a house. Iraqi police said it was shot down.

"The engineers and people investigating the crash are still working," British spokesman Major Sebastian Muntz said, adding that the forces hoped to remove the wreckage later in the day.

Troops were continuing to maintain a security cordon around the crash site, in the city center close to the provincial governor's offices. Iraqi troops and police maintained a heavy presence throughout the city after an overnight curfew.

A local health service official said five Iraqis were killed and 42 wounded in violence after the crash. Some casualties were caused by mortar fire in the area, witnesses said.

British troops fired plastic bullets and, they said, also three live rounds.

Iraqi President Jalal Talabani wrote to British Prime Minister Tony Blair to express his condolences, describing the deaths of those on the helicopter as a "vile crime."