Baghdad, Iraq ? A U.S. military helicopter crashed north of the Iraqi capital Monday – the third American chopper to go down in 10 days – killing the two crew members. A resident said he saw the smoke trail of a missile before the aircraft plunged to the ground.

The military said the AH-64 Apache was conducting a combat air patrol when it went down in an area “known for terrorist activity.” Officials said it was too early to determine the cause of the crash, and the names of the dead soldiers were not released. Apaches hold only a pilot and a co-pilot.

Video footage shot by AP Television News in Mishahda, north of Baghdad, showed smoke billowing from what was reported to be the crash site. Helicopters circled nearby.

Two militant groups claimed they shot down the helicopter. Neither claim could be verified.

Rashid Khalifa, 27, who has a food and drink stand in the area, said he saw the attack. “I saw the smoke trail left by the missile,” he said. “I heard a hissing sound, looked around and saw the helicopter losing control before crashing down.”

The U.S. command questioned the credibility a video purportedly showing an attack on a helicopter that was posted on the Internet by one of the militant groups, the Mujahedeen Army.

The wobbly video showed a militant firing a shoulder-launched missile toward what appeared to be a helicopter in the distance. The aircraft in the video was hit, burst into flames and crashed to the ground.

“A review of the footage on television of a missile being fired does not appear to show this incident today, which remains under investigation,” said Lt. Col. Barry Johnson, a U.S. spokesman.

“This appears to be another case of terrorists attempting to manipulate a tragic incident in the international media and getting the most news value out of it by using footage of something else to gain greater attention,” he added.

The other group that claimed in an Internet posting that it shot down the helicopter was the Salahudin al-Ayoubi Brigade. Both groups have carried out previous attacks.

The number of fatal U.S. military helicopter crashes in Iraq has spiked in recent weeks, fitting a wartime pattern of more frequent accidental and combat crashes during winter months.

An OH-58 Kiowa Warrior reconnaissance helicopter crashed near the northern city of Mosul on Friday, killing two pilots. On Jan. 7, a Black Hawk with 12 aboard crashed in bad weather near the northern city of Tal Afar. All eight soldiers and four civilians aboard were killed.

The causes of those crashes have yet to be announced.

The overall safety record of Army and Marine Corps helicopters has been good, military officials and private analysts say, given the enormous amount of flying in often-harsh conditions.

Army helicopters have logged nearly 1 million flight hours since the Iraq war began in March 2003, with the UH-60 Black Hawk accounting for nearly one-third of the total, according to Army Aviation Warfighting Center records.

Seven Black Hawks have crashed during the war. The second-most heavily used Army helicopter, the AH-64 Apache, has crashed four times and the No. 3 helicopter, the Kiowa Warrior, has gone down seven times. Some were accidents, others were caused by hostile fire and some are still under investigation.