Shelling in Syria's Raqqa kills 20, including eight children

Government shelling in the northern Syrian province of Raqqa killed about 20 people, at least 8 of them children, a video posted by activists on Wednesday showed.

The Syrian Observatory for Human Rights published a video showing rows of the blood-stained bodies laid out on blankets. The sound of crying relatives could be heard in the background.

The shelling hit the province's al-Qahtania village, but it was unclear when the attack happened.

Anti-regime activists say more than 40,000 people have been killed since Syria's crisis began in March 2011.

Meanwhile, the general who heads Syria's military police has defected and joined the uprising against president Bashar Assad.

Major General Abdul-Aziz Jassem al-Shallal appeared in a video aired on Al Arabiya TV saying he is joining "the people's revolution".

In the video aired late Tuesday, al-Shallal said the army deviated from its mission of protecting the nation and became "a gang for killing and destruction".

Dozens of generals have defected since Syria's crisis began in March 2011 but al-Shallal is one of the most senior and held a top post at the time that he left.

In July, Manaf Tlass, a Syrian general, was the first member of Assad's inner circle to break ranks and join the opposition.

The defections, combined with recent gains by rebels in various battlegrounds across the country, suggest that al-Assad is losing his grip on a country that his family has firmly commanded for more than 40 years.

But the president has given no indication that he will step down.