BAGHDAD, Iraq — Some 350 U.S.-trained Iraqi police have been killed in the past year, and rebel attacks will likely increase before the coalition hands over sovereignty on June 30, the U.S. military said Thursday. The latest American casualty was a soldier who died in a bomb explosion north of Baghdad.

Insurgents have struck police north and south of the capital this week. They killed two police who were twin brothers, killed a provincial police chief and ambushed a van carrying police recruits, killing nine.

"We remain concerned at what is clearly a program of intimidation and targeting of not only the Iraqi police service, but all Iraqi government officials," said Brig. Gen. Mark Kimmitt, the U.S. military's deputy director of operations. "A significant number of Iraqi police have been killed in the past year, somewhere in the order of 350."

He said that despite the attacks "on almost a daily basis," morale in the force remained high and no significant drop in recruitment or retention rates had occurred.

Some 200,000 Iraqis are serving in the country's security forces, which include an army, police, border guards and the Iraqi Civil Defense Corps, or ICDC. Guerrillas view them as collaborators with the U.S.-led occupation, and they often make easier targets because they are less well-armed and protected than the U.S. troops who sometimes accompany them on patrols.

Insurgents "know that police are the authority, force and law, and for this reason they carry out these acts," said Nouri Jaber al-Nouri, inspector general of the Interior Ministry. Suicide bombers have also targeted police stations, and a bombing at an army recruiting center in Baghdad in February killed 47 people.

While U.S. troops will remain in Iraq after the June 30 hand-over of power to a transitional government, the coalition wants Iraqi security forces to assume a bigger role in the fight against an insurgency that has claimed hundreds of American lives.

As of Thursday, nearly 600 U.S. service members have died since the beginning of military operations in Iraq a year ago, according to the Department of Defense.

On Thursday, a 1st Infantry Division soldier died and two were wounded when a homemade bomb exploded near Baqouba, the military said. The soldiers went to the area after Iraqi ICDC forces notified them that a homemade bomb had been found. The two wounded soldiers were in stable condition.

In Fallujah, west of Baghdad, insurgents attacked a U.S. military convoy, and TV footage showed an empty Humvee in flames. One Iraqi driver in a civilian car was killed in the crossfire.

A day earlier, a gunbattle with insurgents killed one American soldier and three rebels near Taji, just north of the capital, A U.S. soldier was also wounded.

With fewer than 100 days until U.S.-led occupiers transfer power to Iraqis, U.S. and Iraqi officials expect Iraqi guerrillas and foreign fighters to step up attacks to try to demonstrate that a fledgling Iraqi government cannot control the country.

"The security issue cannot be overemphasized," Mouwaffak al-Rubaie, a Shiite Muslim member of the U.S.-appointed Governing Council.

A senior coalition official said Thursday that the coalition has formed an Iraqi Defense Ministry that will report directly to L. Paul Bremer, the top administrator in Iraq, and will include a counterterrorism unit. The formation of the ministry came nearly 10 months after the coalition dissolved Saddam Hussein's entire security and defense apparatus.

Also Thursday, Chinese President Hu Jintao met in Beijing with Mohammed Bahr al-Ulloum, the head of the Governing Council, to discuss Iraq's political situation and reconstruction efforts. Bahr al-Ulloum thanked Hu for writing off part of Iraq's debts to China, along with Beijing's $25 million pledge to aid reconstruction.

China opposed the U.S. attack on Iraq and has no plans to send troops, but is eager to be commercially involved in the reconstruction.