Iraqi security forces found a mass grave containing about 100 bodies in the volatile Diyala province, the U.S. military said on Saturday.

The Iraqi security forces discovered the site of the mass grave on Friday, and initial reports said it may contain the remains of 100 badly decomposed bodies, the military said in a statement sent to Xinhua by email.

"The skeletal remains appear to have been in the grave for a long time," the statement said.

The U.S. military said that they have not yet determined who might be responsible for the killing and burial, and that the grave site is currently being investigated.

Diyala province, which stretches from eastern edges of Baghdad to the Iranian border, has long been the stronghold of al-Qaida militant groups and hotbed of insurgency and sectarian violence since the U.S.-led invasion broke out in 2003.

U.S. and Iraqi security forces regularly discover mass graves in different parts of Iraq, but the latest one is one of the largest mass graves found in the recent months.

Last month, the Iraqi security forces found a mass grave contained 50 bodies in the open area near the city of Samarra, some 120 km north of Baghdad, during an operation against al-Qaida in Iraq network.

(Xinhua News Agency March 9, 2008)