Syrian security forces have killed more than 100 people since beginning a crackdown on anti-government protesters last week, Al-Arabiya reported on Thursday.

The bodies of at least 25 protesters who died in confrontations with security forces arrive at the main hospital in the restive city of Daraa on Wednesday, a medical official said, after Syrian police launched a relentless assault lasting nearly 24 hours on a neighborhood sheltering anti-government protesters.

Open gallery view Anti-Syrian government protesters in Daraa on March 23, 2011 Credit: AP

"We received them at 5 P.M. yesterday. They all had bullet holes," the official told Reuters.

At least six were killed in a predawn attack on the al-Omari mosque in the southern agricultural city of Daraa, where protesters have taken to the streets in calls for reforms and political freedoms, witnesses said.

An activist in contact with people in Daraa said police shot another three people protesting in its Roman-era city center after dusk. Six more bodies were found later in the day, the activist said.

Around 20,000 Syrians chanting freedom slogans marched on Thursday in the funerals of nine protesters killed by security forces in Daraa, witnesses said.

"God Syria, Freedom. The blood of martyrs is not spilled in waste!" they chanted in Daraa's southern cemetery.

Open gallery view A Syrian soldier, checks his AK-47 as he stands in front the burned court building that was set on fire by Syrian anti-government protesters, in the southern city of Daraa, Syria, March 21, 2011. Credit: AP

Inspired by the wave of pro-democracy protests around the region, the uprising in Daraa and at least four nearby villages has become the biggest domestic challenge since the 1970s to the Syrian government, one of the most repressive in the Middle East.

Security forces have responded with water cannons, tear gas, rubber bullets and live ammunition. The total death toll since the start of protests now stands at 22.

As the casualties mounted, people from the nearby villages of Inkhil, Jasim, Khirbet Ghazaleh and al-Harrah tried to march on Daraa Wednesday night but security forces opened fire as they approached, the activist said. It was not immediately clear if there were more deaths or injuries.

Democracy activists used social-networking sites to call for massive demonstrations across the country on Friday, a day they dubbed 'Dignity Friday'.

Heavy shooting rattled Daraa throughout the day, and an Associated Press reporter in the city heard bursts of semi-automatic gunfire echoing in its old center in the early afternoon.

State TV said that an armed gang had attacked an ambulance in the city and security forces killed four attackers and wounded others.

It denied that security forces had stormed the mosque, but also showed footage of guns, AK-47s, hand grenades, ammunition and money that it claimed had been seized from inside.

A video posted on Facebook by activists showed what it said was an empty street near al-Omari Mosque, with the rattle of shooting in the background as a voice shouts: "My brother, does anyone kill his people? You are our brothers."

The authenticity of the footage could not be independently verified. Mobile phone connections to Daraa were cut and checkpoints throughout the city were manned by soldiers in camouflage uniforms and plainclothes security agents with rifles.

Daraa is a province of some 300,000 people near the Jordanian border that has suffered greatly from years of drought. It has been generally supportive of President Bashar Assad's Baath party, said Murhaf Jouejati, a Syria expert at George Washington University.

He said Daraa had a conservative, devoutly Muslim population that has traditionally been a main pillar of support for the rulling party. The fact that they have been protesting in the streets means that the Baath party is in trouble.

The unrest in Daraa started with the arrest last week of a group of students who sprayed anti-government graffiti on walls in the city of Daraa, some 80 miles (130 kilometers) south of Damascus.

