A U.S. military helicopter crashed near Baghdad on Wednesday, killing seven U.S. military personnel. Four helicopters have been shot down in Iraq in three weeks. The cause of Wednesday's incident was unknown, an army spokesman said.
Following is a list of some incidents in Iraq involving U.S. helicopters since 2005:
January 26, 2005 - A U.S. CH53E transport helicopter crashes close to the Jordanian border in Anbar province, western Iraq, killing 30 Marines and one sailor.
April 28 - Iraqi insurgents shoot down a Bulgarian Russian-built Mi-8 commercial helicopter with 11 people on board, including six Americans. The sole survivor, a Bulgarian crew member, is captured.
November 2 - A Super Cobra helicopter is shot down, killing the two Marine crewmen. Al Qaeda claim responsibility the next day.
January 8, 2006 - A UH-60 Black Hawk crashes near Mosul killing all 12 aboard which included eight service personnel and four civilians.
January 13 - Insurgents shoot down a U.S. military helicopter near the northern Iraqi city of Mosul, killing its two pilots.
January 16 - Both crew members are killed when their Apache attack helicopter comes down in swampland near Taji, north of Baghdad -- apparently brought down by a missile.
April 1 - Two pilots are killed after their AH-64D Apache Longbow helicopter went down due to possible hostile fire west of Yusifiya 15 km (9 miles) south of Baghdad.
May 14 - A U.S. helicopter is shot down during clashes near Yusifiya. Two soldiers are killed.
August 8 - A U.S. Marine helicopter carrying a crew of six crashes in Anbar, west of Baghdad. Two crew are missing.
December 3 - Four U.S. troops are killed when a Marine helicopter twin-rotor Sea Knight with 16 people on board made an emergency landing in a lake in Haditha.
January 20, 2007 - U.S. military UH-60 Black Hawk helicopter shot down northeast of Baghdad, killing all 12 people aboard.
January 23 - Security contractors in two U.S. helicopters attacked. One shot down, killing all four aboard. A fifth contractor was shot dead aboard the second helicopter.
January 28 - Two U.S. soldiers are killed when their Apache helicopter shot down north of the Shi'ite holy city of Najaf.
February 2 - U.S. helicopter shot down northwest of Baghdad, killing two soldiers.
February 7 - A U.S. military CH-46 Sea Knight transport helicopter crashes northwest of Baghdad, killing seven U.S. military personnel aboard.
NOTES: Further details of some U.S. military helicopters:
Apache - Two crew; missile-firing main attack helicopter.
Black Hawk - At least three crew; frontline helicopter, carries 11 combat troops into action; also medical evacuation.
Chinook - Two crew; can carry up to 55 passengers or cargo; twin-engine, tandem-rotor, heavy-lift transport helicopter. The twin-rotor Sea Knight, the Marine version of the Chinook, can carry up to 25 passengers and four crew.
Kiowa - Two crew; armed reconnaissance helicopter.
Super Stallion - A Sikorsky CH53E Super Stallion is a three-engine, heavy-lift helicopter and has a crew of three and can carry up to 55 troops.