Head of Syrian military police defects

General Abdelaziz Jassim al-Shalal, the head of Syria's military police, speaks in a video uploaded on a social media website December 26, 2012.

BEIRUT (Reuters) - The head of Syria's military police has defected from the army and declared allegiance to the uprising against President Bashar al-Assad, according to a video and a Syrian security source.

The high-level defection, while not a strategically significant development in the 21-month-old conflict, will be a blow to morale for Assad's forces, which are hitting back at a string of rebel advances across the country.

"I am General Abdelaziz Jassim al-Shalal, head of the military police. I have defected because of the deviation of the army from its primary duty of protecting the country and its transformation into gangs of killing and destruction," the officer said in a video published on YouTube.

A Syrian security source confirmed the defection but played down its significance.

"Shalal did defect but he was due to retire in a month and he only defected to play hero," the source said.

Wearing a camouflage uniform with red officer insignia on the shoulder, Shalal spoke from a desk in a room in an undisclosed location. Some rebel sources said he had fled to Turkey. It was not clear when Shalal had changed sides.

"The army has destroyed cities and villages and has committed massacres against an unarmed population that took to the streets to demand freedom," he said. "Long live free Syria."

(Reporting by Erika Solomon; Editing by Alistair Lyon)