TAL AFAR, Iraq (Reuters) - A suicide bomber wounded 41 U.S. soldiers and three Iraqis in an attack on a military base in northern Iraq Tuesday while in Baghdad, a car bomb exploded outside a mosque killing three Iraqis.

The attacks coincided with an announcement from Japan that it had approved a plan to send non-combat troops to Iraq, despite strong voter opposition.

The blast at the U.S. base occurred shortly before dawn. The explosives-laden car blew a crater in the street and sent glass and debris flying across a wide area.

"It was definitely a suicide bomb -- there were pieces of the individual all over the compound," said Colonel Michael Linnington of the 3rd Brigade of the 101st Airborne Division.

Most of the U.S. soldiers injured suffered cuts, bruises and broken bones, the military said, but four were more seriously wounded and were evacuated to a military hospital.

An Iraqi translator at the base was also wounded and two Iraqis in the town went to hospital with cuts, a doctor said.

Linnington said soldiers manning the gate at the camp in Tal Afar, 28 miles west of Mosul, had opened fire after the driver charged toward them, ignoring orders to stop.

"The soldiers hit the driver several times, causing him to detonate the bomb prematurely," Linnington said. "He was definitely trying to get through the gate and into the camp."

Nearby, Hazam Ismail's house was littered with debris.

"The explosion shook our doors and windows. The wheel hub of the exploding car smashed through the window of the room where my five children were sleeping," he said. "If any of them had been standing up they could have been killed."

In Baghdad, Iraqi police said explosives placed under a car parked in the grounds of a Sunni mosque were detonated shortly after morning prayers, killing three people and wounding one.

"An explosion rocked the mosque around 6:45 a.m. (10:45 p.m. EST Monday) in the morning. I went to the roof of my house and after three minutes I heard a second explosion," said Ahmed Abdullah, a local resident. There was blood on the ground inside the mosque.

RESTIVE NORTH

U.S. troops in northern Iraq have come under sustained attack in recent weeks, particularly in and around Mosul, Iraq's third largest city. A U.S. soldier was shot and killed in a drive-by shooting in the city Monday and another died in a roadside bomb blast at the weekend.

Late last month the headquarters of the 101st was mortared, killing one soldier. The attacks have been a setback for U.S. commanders, who were praised for bringing a degree of calm and stability to the region in the immediate postwar period.

Linnington said the base at Tal Afar had been attacked by rocket-propelled grenades several times in recent weeks but Tuesday's assault was by far the worst. Soldiers at the base said they were surprised no one was killed.

Since Washington launched the war to overthrow Saddam Hussein in March, 308 U.S. soldiers have been killed in action, 193 of them since President Bush declared major combat over at the beginning of May.

While the U.S. military says the overall number of attacks against troops has declined from as many as 50 a day to around 20 following a recent offensive against guerrillas, November was still the deadliest month for U.S. troops since the war began.

JAPAN TO SEND TROOPS

In a show of support for the U.S.-led coalition, Japan's cabinet approved a plan Tuesday to send troops to Iraq.

The landmark decision, less than two weeks after the killing of two Japanese diplomats in Iraq, clears the way for what could be the biggest and most dangerous overseas mission by Japan's military since World War II.

The plan allows for the dispatch of up to 600 army personnel at any time during a one-year period starting December 15. It does not set a specific date when they will actually be sent.

Prime Minister Junichiro Koizumi, explaining the decision at a news conference in Tokyo, said troops would not engage in active duties and would be in Iraq solely for reconstruction.

"They will not exercise military force, they are not going there to stage war," Koizumi told reporters.

The relentlessness of the insurgency in Iraq has also had an impact on those allied to or backed by the U.S.-coalition. Iraqi police have been repeatedly attacked recently and contractors working to rebuild infrastructure have also been targeted.

Monday, a group of South Korean electrical workers left Baghdad for Jordan following the killing of two of their colleagues by guerrillas late last month.