6:26pm UK, Tuesday August 30, 2011

Emma Hurd, Middle East correspondent

Security forces in Syria have opened fire on demonstrators, killing at least seven people including a 13-year-old boy, according to activists.

Protesters were reportedly shot at in the towns of al Hara and Inkhil as they emerged from mosques, after morning prayers to mark the end of the holy fasting month of Ramadan.

Thousands of people joined demonstrations elsewhere across the country, demanding the downfall of President Bashar al Assad, despite the heavy presence of tanks and troops in many cities.

In the suburbs of the capital, Damascus, witnesses said people spilled out of the mosques to take part in street protests on the first day of the Muslim holiday of Eid al Fitr.

Units of security forces, armed with AK-47s, have moved into the areas around the mosques and the cemeteries, where people traditionally spend the day visiting the graves of their dead relatives.

But the continuing crackdown has failed to halt the protests.

Activists claim dozens of Syrian troops have defected in recent days after refusing to fire on their own people.

The defecting soldiers are from the majority Sunni population but are commanded by Alawite officers who remain loyal to Mr Assad.

In the city of Homs, the mass defection of a group of soldiers prompted a firefight which left at least one woman dead.

The Syrian National Human Rights Organisation claims 3,100 civilians have been killed by the security forces and their loyalist militias since the protests began in March.

The UN, which puts the figure at 2,200, has launched an investigation into crimes against humanity in Syria.

A makeshift gallows with a poster showing Mr Assad

Mr Assad has so far ignored growing international pressure to halt the violence, including the threat of increased sanctions that might lead to an oil embargo.

But his once-trusted allies appear to be losing faith in his ability to stabilise Syria through brute force alone.

Even Iran, which has largely stayed silent throughout the bloodshed, has called for negotiations with the protesters.

Tehran fears the ousting of Mr Assad will reduce its influence across the region.