Its approval came after a bomb killed 19 people and wounded 58 in a Shiite district of Baghdad, while police also found the bodies of 19 Iraqis who apparently had been kidnapped and tortured by death squads that plague the capital and other cities.

Despite the violence, legislators at Baghdad's heavily fortified Green Zone approved Prime Minister-designate Nouri al-Maliki's new Cabinet.

Cabinet members for the crucial national security, interior and defence ministries have still not been agreed; for now Prime Minister alMaliki, a Shia, will run the interior ministry and deputy Prime Minister Salam Zaubai, a Sunni, will run defence. The former deputy speaker Hussain al-Shahristani, a Shia, will take on the key role of oil minister.

The United States hopes the new national unity government of Shiites, Sunnis and Kurds can calm the violence and pave the way for Washington to begin withdrawing troops.

"This is a historic day for Iraq and all its people, " deputy parliament speaker Khalid al-Attiyah said at a nationally televised news conference as the legislators gathered.

"It is the first time that a fullterm, democratically elected government has been formed in Iraq since the fall of the ousted regime.

This government represents all Iraqis, " said al-Attiyah, a bearded Shiite cleric wearing a white turban.

The challenge the new government will face was apparent on Friday when al-Maliki failed to reach agreement with political leaders on who would run the key defence and interior ministries.

His decision to push ahead with forming a government was yet another sign of his determination to waste no time addressing Iraq's security . . . his administration's top priority.

At 6.30am yesterday, several hours before legislators began to arrive at the Green Zone, suspected insurgents set off a bomb in a Shiite district of Baghdad, killing 19 people and wounding 58, police said. The blast happened near a food stand in Sadr City where men gather to wait for jobs as day labourers, police Major Hashim al-Yaser said.

"It was a huge explosion, " said Mohammed Hamid, who works in a bakery in the area. "We carried many of the injured to ambulances and helped remove the bodies."

Sadr City is the stronghold of radical Shiite cleric Muqtada al-Sadr, who operates a powerful militia, one of many that exist in the capital outside the control of the government.

Al-Maliki hopes to disband such militias and integrate them into the country's military and police forces as a way of reducing violence.

Elsewhere, police also found the bodies of 19 people who apparently had been kidnapped and tortured, four in Baghdad and 15 in Musayyib, about 40 miles south of the capital. It was unclear when the victims in Musayyib had been killed.

However, all 19 bodies appeared to be victims of death squads which kidnap and kill hundreds of people in Iraq, to settle personal vendettas, because of sectarian hatred, or in an effort to win ransoms.