Baghdad, Iraq ? Al-Qaida in Iraq claimed Thursday it shot down a U.S. attack helicopter that crashed, killing two Marines, and a U.S. general said witnesses saw the aircraft take ground fire and break up in the air.

The AH-1W Super Cobra crashed Wednesday near Ramadi during daylong fighting in the insurgent stronghold 70 miles west of Baghdad. In addition to the two crewmen, an American lieutenant died when a bomb exploded as he was rushing to the crash site.

Another U.S. soldier died Thursday in a roadside bombing northeast of Baghdad, the military said.

In its statement, al-Qaida in Iraq, led by Jordanian terror mastermind Abu Musab al-Zarqawi, said that its military wing “downed a Super Cobra attack helicopter in Ramadi with a Strella rocket, thanks be to God.”

The authenticity of the statement could not be determined. It appeared on an Islamic Web site and bore the nickname of the group’s spokesman, Abu Maysara al-Iraqi. The U.S. military said the cause of the crash had not been determined.

However, Maj. Gen. Rick Lynch told reporters Thursday that witnesses “believe they saw a munition fired at the helicopter and saw the helicopter break in pieces in midair and then crash.”

In Burlington, Vt., Maj. Gen. Martha Rainville, the adjutant general of the state’s National Guard, said 2nd Lt. Mark Procopio, 28, of Burlington, was killed Wednesday by the roadside bomb as his patrol of four Humvees and two tanks headed to secure the crash site.

An Iraqi boy cries as a child, who was found dead in the rubble of collapsed homes, is buried Thursday in Ramadi, Iraq. According to local residents, the homes collapsed Wednesday after a U.S. fighter jet dropped two bombs on what the U.S. military described as an insurgent

“He and his patrol were on a routine mission when they saw a Marine helicopter coming under fire, realized it was going to crash and responded to provide assistance as necessary and to secure the site,” Rainville said. The Humvee in which Procopio was riding struck the bomb, and he was killed instantly, she said.

On Thursday, another U.S. soldier died in a roadside bombing near Baqouba, 35 miles northeast of Baghdad. The soldier’s name was not released, but the U.S. command said he was assigned to the Army’s 43rd Military Police Brigade.

The soldier’s death raised to at least 2,037 the number of U.S. military service members who have died since the war began in 2003, according to an Associated Press count. It was also the eighth battle death among the 157,000-member U.S. force in November. October was the fourth deadliest month for American service members since the conflict began.

Roadside bombs, which the U.S. military refers to as “improvised explosive devices,” or IEDs, have accounted for most of the recent U.S. battle deaths, despite a vigorous campaign to improve armament on American vehicles and to hunt down insurgent weapons caches.

Last week, for example, 40 percent of the attacks against U.S. and coalition forces were carried out with IEDs, Lynch said. But they accounted for 64 percent of the U.S. and coalition casualties, he said.

Lynch declined to talk in detail about increased sophistication of roadside bombs, including the use of infrared triggers. British officials say they have seen the use of infrared triggers in attacks against their own forces and suspect the technology has been supplied by Iran, a charge the Iranians have denied.