BAGHDAD — A suicide car bomb exploded Wednesday at a police checkpoint guarding a courthouse in Ramadi, killing at least six people in the largest attack on Anbar province's capital in months, police said.

The dead included three women, said Col. Jubair Rashid Naief, a provincial police official. Another 13 people were wounded, he said.

Ramadi, 70 miles west of Baghdad, was once a base for Sunni insurgents but has seen a huge security improvement since many Sunni tribesmen began partnering with U.S. forces last year.

The U.S. military said a sophisticated roadside bomb killed a U.S. soldier and an Iraqi interpreter and wounded three other soldiers on patrol Tuesday in eastern Baghdad. The soldiers were returning to a U.S. base after conducting an escort mission when they were struck by an explosively formed penetrator, or EFP, the military said.

EFPs fire a slug of molten metal capable of penetrating even the most heavily armored vehicles, and are have been responsible for hundreds of U.S. deaths in Iraq.

At least 3,874 members of the U.S. military have died since the beginning of the war in 2003, according to an Associated Press count.

Iraqi security troops, meanwhile, unearthed six decomposed bodies in southern Baghdad. The bodies were buried in the backyards of residents who had fled violence in their Saydiyah neighborhood, said army Col. Jabbar Hussein.

AP Television News video showed soldiers in white surgical masks wrapping the mud-coated bodies in blankets and black plastic bags and loading them into the back of a pickup truck. It was unclear when the victims died.

The U.S. military also said six suspected militants were killed and 10 captured in two days of raids across central and northern Iraq.

Other scattered attacks were reported Wednesday around the country. The deadliest occurred when gunmen attacked a police patrol in downtown Muqdadiyah, about 60 miles north of Baghdad, police said.

A police officer was also killed in a drive-by shooting in central Kut, 100 miles southeast of the Iraqi capital, police said.

On Tuesday, a British Puma helicopter crashed southeast of Baghdad, killing two soldiers and seriously injuring two others, Britain's Ministry of Defense said. The cause of the nighttime crash was not immediately known, it said.

Earlier, the U.S. military said an investigation was under way, but initial reports indicated it was not due to hostile fire.

The U.S. put the total number of injured at 12 and did not specify the severity of injuries.

Violence has declined sharply in Iraq in recent months, due in part to stepped up U.S. military activity, a decision by the biggest Shiite militia to suspend operations and the Sunni Arab revolt against al-Qaida in Iraq.

The U.S. general in charge of training and equipping Iraqi forces said that overall, Iraq's security situation is "better than it has been in previous months."

"It's certainly much better than earlier this year," said Lt. Gen. James Dubik, commander of Multi-National Security Transition Command.

"But this is an enemy that is cunning, ruthless and desirous to figure out another way to re-engender violence and steal away security gains from the Iraqi people," Dubik told reporters in the U.S.-guarded Green Zone.