A suicide bomber killed at least 13 people and wounded 17 when he blew himself up in a downtown Baghdad restaurant frequented by police.
The attack on the Safar restaurant was part of a spree of roadside bombs, mortar rounds and a drive-by shooting that killed at least 17 Iraqis and wounded dozens on Sunday.
They served as a fresh reminder of the task that Nuri al-Maliki faces in reining in bloodshed.
The Shia prime minister, briefing reporters after the cabinet meeting on Sunday, said his government would hold out the offer of dialogue to those prepared to renounce violence. He vowed to reimpose the state's monopoly on the armed forces, cracking down on militias.
"We will use maximum force against terrorism, but we also need a national initiative," he said.
An Arab League national reconciliation meeting is to take place next month in Baghdad.
"Weapons should only be allowed in the hands of the government. Militias, death squads, terrorism, killings and assassinations are odd cases and we should put an end to the militias," al-Maliki said.
As the cabinet met for the first time since Saturday's swearing-in in parliament, a car bomb killed three people and wounded 15 in Baghdad's western mainly Shia Shula district. A bomb in a restaurant in the downtown Karrada district killed four people and wounded five, police said.
Earlier, a roadside bomb on the eastern bank of the Tigris killed three people and wounded 24 in a blast apparently targeting Iraqi police in a busy commercial street.
Since the cabinet was sworn in on Saturday, more than 30 people have been killed in a series of attacks across Iraq, and police have found the bodies of 22 Iraqis who apparently had been kidnapped and tortured by death squads that plague the capital and other areas.
A blast in Baghdad's Sadr City
killed 19 people on Saturday
On Saturday, al-Maliki and his 40-member cabinet took the oath of office inside the heavily fortified Green Zone in central Baghdad, where American and Iraqi soldiers provide security from the turmoil sweeping the country.
After a two-hour delay, reportedly because of last-minute wrangling over some cabinet posts, legislators dressed in suits or traditional Arab robes slowly filed into the parliament chamber. Outgoing members of the interim legislature greeted each other with kisses to the cheeks.
The vote of approval went quickly, with parliament members elected in December 15 elections waving raised hands to ratify al-Maliki's nominees one by one.
US, UK approval
George Bush, the US president, who is facing rising criticism at home over Iraq, welcomed the new cabinet and promised continued help from the United States.
"The United States and freedom-loving nations around the world will stand with Iraq as it takes its place among the world's democracies and as an ally in the war on terror," Bush said in a statement.
Bush welcomed the new cabinet
and promised continued help
Zalmay Khalilzad, the US ambassador in Iraq, repeated US cautions against expectations of a quick pullout of the 132,000-strong American military contingent. But, he added, that "strategically, we're going to be moving in the direction of downsizing our forces".
Tony Blair, the British prime minister, said: "Despite all the attempts to disrupt the political process they have a government, a government ... of national unity for the first time."
Blair said multinational soldiers hoped to transfer their duties to Iraqis as soon as possible, but that British troops would remain in Iraq for as long as they were needed.
"The timetable is governed by the job being done. The new prime minister today made it very clear he, like us, wants to see Iraq in control of its own destiny," Blair said.
Al-Maliki outlined a 34-point plan to bring security, implement the rule of law and restore basic services like electricity - now available for only four hours a day in the capital.
In a sign of the divisions that held up forming the government, al-Maliki could not work out an agreement on the cabinet's three posts responsible for security and had to appoint himself and two deputy prime ministers to temporarily hold those positions.
Winning over Sunnis will be a big
challenge for al-Maliki
Hussain al-Shahristani, the Shia Muslim chosen as oil minister, promised to increase oil production and give all Iraqis a share.
"For every Iraqi, a share in the oil wealth," al-Shahristani said.
As for the three unfilled posts, al-Maliki said he would be acting as interior minister for now, and he tapped Salam Zikam al-Zubaie, his Sunni Arab deputy prime minister, as temporary defence minister.
Barham Saleh, the deputy prime minister, and a Kurd, will be acting minister of state for national security.
The new prime minister hopes to fill the jobs with politicians who are independent and have no affiliation with any of Iraq's sectarian militias, which are blamed for the sharp rise in Shia-Sunni bloodshed that has raised fears of civil war.
The greatest drama of the day underlined the difficulties al-Maliki faces in calming those sectarian passions.
Sunni Arab lawmaker Saleh al-Mutlaq demanded that the government's swearing-in be postponed until the security ministries were allotted, delivering an angry speech that lasted nearly 10 minutes before the microphone was taken away.
"Despite all the attempts to disrupt the political process they have a government ... of national unity for the first time"
British Prime Minister Tony Blair
Then he and about 10 other Sunni deputies from his Arab nationalist faction walked out in protest.
Many of Iraq's anti-government groups are led by Sunni Arabs, and a goal of the new government is to win the support of that formerly dominant minority and to recruit as many of them as possible into Iraq's security forces - especially in anti-government strongholds like western Anbar province.
One of Saturday's attacks, a suicide car bombing at a police station that killed at least five people and wounded 10, took place in Anbar city of Qaim.
In the day's deadliest assault, 19 people died when a bomb hidden in a paper bag exploded in Baghdad's Sadr City district next to a line of day labourers waiting for work.