A suicide bomber blew up explosives in his car outside the house of a police chief south of Baghdad on Tuesday, killing himself and wounding seven others, officials said. The attack came after the head of a U.N. team said better security is vital if Iraq wants to hold elections by a Jan. 31 deadline.

West of Baghdad, one American soldier was killed and a second was wounded by a roadside bomb Tuesday, the U.S. military said.

The injured soldier was airlifted to a combat support hospital after the explosion near Ramadi, said Brig. Gen. Mark Kimmitt (search), the military's deputy director of operations.

U.S. Marines operate in the area, but Kimmitt did not say whether the casualties were Marines.

In Ramadi, west of Baghdad, a U.S. Humvee was hit with a rocket-propelled grenade Tuesday, setting it on fire, witnesses said. Four soldiers who were in the vehicle were seen being rushed away in another Humvee. A U.S. spokeswoman in Baghdad could not confirm the attack.

It was unclear whether the two incidents were related.

In the southern city of Najaf (search), Iraqis protesting delays in processing their applications for police jobs hurled stones at Spanish soldiers and Iraqi police, smashed windows and burned a guardhouse, witnesses said.

Witnesses also reported gunfire during the three-hour riot, and at least three police officers and two protesters were wounded.

Spanish radio station Cadena Ser reported that a female Spanish soldier and five Iraqis were injured, but the Spanish Defense Ministry in Madrid denied that a Spanish soldier was injured.

The suicide bombing occurred in the town of Hillah (search), about 60 miles south of Baghdad, near where another police chief was shot and killed a week ago and nine police recruits died when assailants sprayed their minibus with small-arms fire.

Police Maj. Ali Jawad said guards outside the house of Hillah police chief Brig. Gen. Qeis Hamza opened fire at the car when they saw it speeding toward them, but failed to stop the attacker.

Four of those wounded were guards, while the other three were residents of nearby houses, Jawad said. Hamza and his family, who were home at the time of the blast, were unhurt. The explosion damaged the chief's house and those of his neighbors.

Guerrillas often target the police because they view them as collaborators with the U.S.-led occupation, and they often make easier targets because they are not as armed and protected as U.S. troops.

East of Baghdad in Diala province late Monday, a U.S. soldier from the 3rd Brigade of the 1st Infantry Division was wounded when a rocket-propelled grenade was fired at an Army convoy, a U.S. official said on condition of anonymity.

Also Monday, west of Baghdad, a bomb that exploded near a U.S. military convoy killed an American soldier, a U.S. official said. The attack occurred northwest of the town of Fallujah, where anti-U.S. guerrillas are active.

In the southern city of Basra, British troops with clubs and shields fought Monday with dozens of anti-coalition Iraqis, who resisted eviction from a government-owned building. At least four Iraqis were injured. Two British soldiers suffered minor injuries, the British Ministry of Defense said.

In Baghdad on Monday, a U.N. team met members of the U.S.-appointed Iraqi Governing Council, discussing the creation of an interim government ahead of a June 30 transfer of power from the U.S.-led coalition to Iraqis and plans for general elections after that.

Carina Perelli, leader of the U.N. team, told reporters that security was key.

"We need to make sure that between now and the 31st of January, there is a modicum of security that will make Iraqi people feel they can go to the polls, that they can run as candidates, without extreme fear," she said after the two-hour meeting.

"We put the expertise and the experience of the U.N. at the disposition of the Iraqi people in terms of the assistance it might need in carrying out this process."

Perelli said the U.N. team, the Governing Council and the coalition had to move quickly to meet the election deadline. Her team arrived Friday and will stay for several weeks. A second U.N. delegation is expected in early April.

"If there is going to be an election on the 31st of January, then all the basic agreements need to be reached for the electoral frame no later than the end of May. Otherwise, the date might be compromised," she said.

Mohsen Abdel-Hamid, a Sunni member of the Governing Council, said many council members "spoke about elections and ways of protecting these elections and the mechanism that should be used in order for the election not to be fixed."

Abdel-Hamid said the goal was to conduct clean elections and "achieve the hopes of the Iraqi people, who have been deprived of elections for decades under a dictatorship."

In New York, meanwhile, U.N. Secretary-General Kofi Annan fired a senior official, Tun Myat, for failing to properly protect staff before the Aug. 19 bombing of U.N. headquarters in Baghdad that killed 22 people, including a top envoy.

Annan said Myat and others "appeared to be blinded by the conviction that U.N. personnel and installations would not become a target of attack, despite the clear warnings to the contrary."

In Washington, NATO's most senior civilian official said the alliance might be willing to command part of an international security force for Iraq if the Security Council authorizes it.

NATO Secretary-General Jaap de Hoop Scheffer said NATO might get involved if the Security Council passed a resolution and if the governing body that takes political control in Iraq from the United States on June 30 asked for troops.