One U.S. soldier was killed Thursday in an bomb attack, a day after another American died when a convoy came under hostile fire.

A homemade bomb exploded in Baqouba (search), 40 miles north of Baghdad, killing one soldier from the 1st Infantry Division (search) and wounding two others, according to the U.S. military.

And in a separate incident Wednesday, a U.S. convoy traveling just 12 miles north of the Iraqi capital city was attacked and a gun battle ensued – leaving one American soldier dead and other injured. Three rebels were also killed.

West of Baghdad, in Fallujah (search), rebels hit a convoy transporting goods for coalition forces Thursday.

U.S. troops arrived on the scene and exchanged fire with the rebels, but there were no immediate reports of any American casualties. One Iraqi driver in a civilian car was killed in the crossfire. TV footage showed an empty Humvee in flames.

The latest violence came amid warnings that attacks would likely increase with fewer than 100 days left before the U.S.-led Coalition Provisional Authority hands over sovereignty.

The 1st Infantry Division soldiers went to the Baqouba location after Iraqi security notified them that a homemade bomb had been found. The two injured soldiers were in stable condition.

The gun battle that killed a U.S. soldier occurred Wednesday near Taji (search), just north of the capital, said Brig. Gen. Mark Kimmitt (search), the U.S. military's deputy director of operations. A U.S. soldier was also wounded.

On Tuesday, guerrillas attacked a patrol in the town of Hamam al-Alil, 210 miles north of Baghdad, wounding a U.S. soldier, Kimmitt said. Troops returned fire and killed one attackers.

He said the military was worried by attacks on Iraqi police. On Wednesday, the police chief of southern Babil province was shot and killed. A day earlier, nine police recruits were killed in a nearby attack on their vehicle.

"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," Kimmitt said. "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.

'The Security Issue Cannot Be Overemphasized'

With fewer than 100 days until U.S.-led occupiers transfer power to Iraqis on June 30, U.S. and Iraqi officials expect Iraqi guerrillas and foreign fighters to step up attacks to try to disrupt the handover process and 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.

L. Paul Bremer (search), the top administrator in Iraq, said Wednesday that significant steps had been taken to rebuild the country since a U.S.-led invasion toppled Saddam Hussein a year ago.

"One hundred days from now, Iraqis will be sovereign in their own land and responsible for their own future," Bremer said in an outdoor speech in the Green Zone, the heavily protected area housing the coalition headquarters in the center of Baghdad.

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

Bremer said Wednesday he will set up a national security Cabinet later this week.

He also said he was in the midst of appointing inspectors general to each of Iraq's 25 government ministries while creating an auditing board and an anti-corruption commission. Bremer said work was under way to establish a public broadcasting service and an independent panel to regulate it.

Bremer already has appointed most Iraqi ministers, many of whom are expected to keep their jobs after the handover. He is sorting through the ministers' choices for deputies.

Enormous tasks remain before the handover. The biggest involves anointing an Iraqi transitional government that will take power on June 30 — but the Governing Council and occupation figures have yet to agree upon a plan to name those who will govern.

"We're moving at rocket speed," al-Rubaie said. "The counting down has started."

China Discusses Iraq

Also Thursday, Chinese President Hu Jintao (search) met in Beijing with Mohammed Bahr (search), 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 it has made no secret of its eagerness to be commercially involved in the reconstruction.

Telecommunications firm Zhongxing Telecom Co. won a contract last month to supply equipment to Iraq. That deal was reportedly reached over coalition objections, although U.S. officials have since said they welcome Chinese firms' involvement in reconstruction.

Fox News' David Piper and The Associated Press contributed to this report.