A video showing more than a dozen bloodied corpses emerged in Syria on Friday, in what the government said was a “massacre” by rebels in the northern province of Aleppo.

The Associated Press reported that some of the bodies in the video were seen piled on top of each other and in military uniforms.

The circumstances of the killings were not immediately clear, but the video’s narrator said the dead were members of the “shabiha,” or pro-regime gunmen.

AP quoted Syria’s state-run news agency, SANA, as having said terrorist groups had killed and mutilated at least 25 people in Daret Azzeh, a rebel-held area in the Aleppo countryside.

The government refers to rebels as terrorists.

“The terrorist groups in Daret Azzeh committed a brutal massacre against the citizens, whom they had kidnapped earlier in the day,” SANA said, adding that at least 25 people were killed, but others were missing.

Daret Azzeh has endured intense government shelling over the past two weeks as Assad’s forces try to regain areas taken by rebels.

Shabiha often operate as hired enforcers for Syrian President Bashar Assad’s regime. Shabiha thugs are known to frequently work closely with soldiers and security forces, but the regime never acknowledges their existence – allowing it to deny responsibility for their actions.

They were recently fingered by the UN as having carried out the massacre which killed more than 100 people in Houla.

Meanwhile on Friday, the Britain-based Syrian Observatory for Human Rights said that four senior army officers have defected from the regime. The group provided a video purporting to show two brigadier generals and two colonels who declared they were joining the opposition.

The group said the defections came on Thursday, the same day a Syria fighter pilot defected and flew his MiG-21 warplane to neighboring Jordan, where he was given asylum.

U.S. officials told The Daily Telegraph on Friday that members of Assad’s inner circle are secretly making plans to defect to the opposition should the Syrian regime become critically threatened by the rebellion.