BAGHDAD - A suicide car bomber struck a checkpoint protecting the compounds of Iraq's former prime minister and a Sunni lawmaker yesterday, killing two guards in a neighborhood bordering the fortified Green Zone.

Both men were out of the country, as is common for Iraqi politicians, many of whom maintain homes abroad and are frequent targets for assassination. It was the second bombing in two days apparently targeting Ayad Allawi, Iraq's first post-Saddam Hussein prime minister.

The bombing took place in western Baghdad, less than a quarter mile from buildings that include the home and office compound of Allawi, a secular Shiite, and the offices of Saleh al-Mutlaq, the head of the Iraqi National Dialogue Front, a Sunni political group.

Hussam al-Azawi, a member of Allawi's party, said there had been indications of an assassination plot before the suicide attack.

"The threats and plots came from a neighboring country," he said, without naming the country.

On Monday, police said a roadside bomb had targeted a vehicle carrying guards for Allawi in the same neighborhood. Two guards were injured, as were three policemen and a civilian.

Mutlaq, speaking from Amman, Jordan, said that when the suicide bomber reached the first checkpoint, "he claimed that he was an employee and had access."

"Everyone is vulnerable," he told Al-Arabiya television. "We have been targeted by three groups - the Americans, Iraqi forces, and a suicide bomber."

In January, six Iraqis were killed in a U.S.-led raid on other offices for Mutlaq. The U.S. military and Iraqi police said they suspected the offices were being used as an al-Qaeda in Iraq safe house.

Three Iraqis are on trial in Germany for plotting Allawi's death in 2004 during a visit to Berlin, including one convicted of supporting the radical Islamic group Ansar al-Islam.

In a statement, Allawi's Iraqi National Accord party said it had informed the United States, the United Nations, and the Iraqi government of a new plot against Allawi. "Unfortunately, no action was taken," the party said.

While violence has subsided in Baghdad since summer, when U.S troops flooded into the capital, a recent upsurge in attacks underscores the fragility of the gains.

Gunmen on motorcycles fatally shot the chief of Iraq's largest psychiatric hospital as he was returning home from work late Monday, police and a Health Ministry official said, speaking on condition of anonymity because they feared reprisal.

Dr. Ibrahim Mohammed Ajil was the head of Rashad Hospital, Iraq's largest mental institution, which lies on the outskirts of the sprawling Sadr City district of Baghdad.

Senior U.S. Brass Changing in Iraq

The U.S. military in Iraq

is undergoing its biggest routine changeover in senior commanders since Gen. David H. Petraeus launched

a counterinsurgency nearly a year ago.

Topping the list

of departures is Petraeus' second-in-command, Army Lt. Gen. Ray Odierno, who is due to leave in February when the Third Corps returns to Fort Hood, Texas. He will be replaced by Lt. Gen. Lloyd J. Austin 3d, commander of the

18th Airborne Corps, from Fort Bragg, N.C.

Maj. Gen. Jeffery

W. Hammond, commander of the Fourth Infantry Division, takes charge

of U.S. forces in Baghdad on Dec. 19.

- Associated Press

Iraqi Prime Minister

Nouri al-Maliki wrote to the U.N. Security Council to extend the mandate of U.S.-led forces in the country "one last time" and said the Iraqi army intended to take full control by the end of next year.

The United States

and Iraq plan to negotiate

an agreement on the presence of U.S. troops in Iraq after 2008.

- Bloomberg News