Updated

Roadside bombs killed four U.S. soldiers in Iraq on Tuesday, the military said, in the deadliest day for American troops in the country in weeks, as a series of bomb attacks along roads claimed eight Iraqi lives.

The first roadside bomb struck a patrol in southern Baghdad, killing one American soldier, the military said. A short time later, another bomb targeting a patrol in northern Iraq killed three soldiers, the military said.

The U.S. military, which pulled back from populated areas of Iraq before the end of June, has suffered fewer casualties in recent weeks. In August, seven U.S. troops died — the lowest monthly toll since the war began in March 2003.

Tuesday marked the deadliest day for U.S. forces since June 29, when four soldiers were killed by a roadside bomb in Baghdad.

In all, at least 4,343 U.S. service members have died since the war started in March 2003, according to an Associated Press count.

The attack on the troops was one of a series of roadside bombings around the country.

An explosion killed the head of an Iraqi anti-terrorism police unit and four of his bodyguards in a northern town that is home to large Shiite population, said Brig. Sarhat Qader of the police in Kirkuk, a city farther north.

The town, Armili, has about 26,000 residents — most of them Shiites from Iraq's Turkomen ethnic minority — and has been attacked before. In 2007, a suicide truck bomber struck a market there, killing more than 100 people.

After Tuesday's bombing, armed relatives of those killed went looking for the assailants, who they believed had come from a nearby Sunni village, setting off a gunbattle. Iraqi army troops intervened and there were no casualties.

Insurgents in northern Iraq, who have maintained a stronghold in the city of Mosul, have frequently targeted ethnic minorities in recent weeks. Many of the attacks have hit remote villages and towns like Armili that often depend on a small security force for protection.

Not far from Armili, another roadside bomb struck a police patrol near the town of Daqouq on Tuesday, killing two policemen and wounding three others, Kirkuk police said.

The violence that continues to plague Iraq's north and the capital has forced the government to acknowledge gaps in security. In particular, the government has been criticized for lapses that allowed a devastating attack last month on the foreign and finance ministries.

On Tuesday, the spokesman for Baghdad's security command center told a news conference that 29 police and army officers arrested after the August attack were charged with negligence. All were responsible for security in the areas of the two ministry buildings, said Maj. Gen. Qassim al-Moussawi.

He also put the official death toll in the Aug. 19 bombings at 92, lower than figures provided by Iraqi police showing at least 101 dead.

One of those suspected of direct involvement in the attack said in a televised confession shortly after his arrest that the bombers were able to pass checkpoints with the payment of bribes.

"There was clear negligence from the security forces," al-Moussawi said.

He also acknowledged more broadly the need to improve the country's U.S.-trained security forces.

"Absolutely, what has been achieved so far in the intelligence and security efforts is below expectations. There is a review to all security plans with the supervision of the prime minister," he said.

Also in Baghdad, a Health Ministry official escaped an assassination attempt Tuesday when a roadside bomb hit his convoy in the eastern part of the capital, but one ministry employee died in the blast, Iraqi police and health officials said.

Eight bystanders and four people in the convoy were also wounded in the attack, which appeared directed at Dr. Ali Bustan al-Fartosi, who is in charge of eastern Baghdad's medical facilities. The doctor escaped unharmed, the officials said.

North of the capital, in the city of Tikrit, a roadside bomb targeting the convoy of the deputy provincial governor injured one of his bodyguards. The deputy governor was unharmed, police said.

All the police and health officials spoke on condition of anonymity because they were not authorized to release the information.