Car bombs and drive-by shootings killed 17 people Monday, including seven police officers, hours before Iraq's parliament met for its first session after swearing in a new government.

The violence also came as British Prime Minister Tony Blair became the first world leader to visit Baghdad since the national unity government took office two days ago. The visit was aimed at shoring up international support for the government as it comes to grips with the security crisis.

CountryWatch: Iraq

Prime Minister Nouri al-Maliki has made security the top priority of his government, a point he stressed during a meeting Sunday with Iraq's military commanders.

"Our country is undergoing serious challenges," al-Maliki said. "We need to think about the pictures shown on satellite channels."

A roadside bomb killed four police officers after exploding next to a patrol in Musayyib, about 40 miles south of Baghdad, police Col. Ahmed Mijwel said.

A car bomb exploded in Baghdad between a clinic and a market in a Shiite neighborhood, killing four people and wounding another nine, 1st Lt. Haider Hamil said.

Another bomb killed five people and wounded four people when it went off next to a patrol in southeastern Baghdad's Zafaraniya neighborhood, said police Capt. Ali Mahdi.

Another roadside bomb missed a police patrol in eastern Baghdad Baladiyat's neighborhood, wounding two civilians, police Lt. Ali Mitaab said.

Officials said gunmen killed a police colonel in Samarra, north of Baghdad, an employee of a cell phone company in Baqouba, and the general director of the youth ministry in Baghdad.

The body of a police captain who had been shot in the head was found in the Aziziya area, south of Baghdad, officials said.

Blair, who held a news conference after a meeting with al-Maliki, said establishing democracy had taken longer than expected following the U.S.-led invasion in 2003, and he refused to set a timetable for the withdrawal of the 8,000 British troops in Iraq.

"It has been longer and harder than any of us would have wanted it to be, but this is a new beginning and we want to see what you want to see, which is Iraq and the Iraqi people to able to take charge of their own destiny and write the next chapter of Iraqi history themselves," he said.

Al-Maliki has promised to use "maximum force" if necessary to end the insurgent and sectarian violence wracking the country. Although he focused on ending the bloodshed, he also has stressed the need to complete unfinished political negotiations.

He said that appointing chiefs for the key Defense and Interior ministries should not "take more than two or three days." He is seeking candidates who are independent and have no ties to Iraq's myriad armed groups.

The two ministries, which oversee the army and the police, are crucial for restoring stability, and al-Maliki needs to find candidates with wide acceptance from his broad-based governing coalition of Shiites, Sunni Arabs and Kurds.

Failure to set the right tone could further alienate the disaffected Sunni Arab minority, which is the backbone of the insurgency. Or it could anger Shiite militias, some of which are thought to number in the thousands.

"We are aware of the security challenge and its effects. So we believe that facing this challenge cannot be achieved through the use of force only, despite the fact that we are going to use the maximum force in confronting the terrorists and the killers," al-Maliki said.

Disarming militias, whose members are believed to have infiltrated the security services, will be a priority, he said, along with promoting national reconciliation, improving the country's collapsing infrastructure and setting up a special protection force for Baghdad.

Many Sunni Arabs think Shiite militias are behind death squads blamed for escalating sectarian violence, leaving dozens of bodies to be found scattered around Iraq every day.

Shortly after Iraq's first Cabinet meeting, a homicide bomber killed at least 13 people and wounded 17 by blowing himself up among filled lunch tables in a downtown Baghdad restaurant popular with police officers. Three of the dead were policemen.

U.S. Ambassador Zalmay Khalilzad said the new government must "get the security ministries to transform in such a way that they will have the confidence of the Iraqi peoples."

"The next six months will be truly critical for Iraq," he said in an interview with The Associated Press.