DAMASCUS: Clashes between Syrian forces and deserters killed 11 people in a village in Hama province Friday, while another eight died during a crackdown on protests in flashpoint Homs, rights activists said.

The killings came as thousands of protesters took to the streets on the Muslim weekly day of prayer that is a lightning rod in the six months of anti-regime protests in which the UN says 2,700 people have been killed by a fierce crackdown.

The activists said those killed in Homs province were shot dead by security forces who opened fire on protesters, even as around 250 tanks and armoured vehicles entered Rastan, a major city in the province where there have been intense military operations against army defectors for days.

"Five civilians and six military and security agents have been killed today in the village of Kafar Zita during clashes between soldiers and agents on one side and deserters on the other," said the Syrian Observatory for Human Rights.

"Eight civilians were killed Friday in Homs province" by security force fire, added the Britain-based Observatory.

Much of the action centered on Rastan, about 180 kilometres (120 miles) from Damascus and a gateway to the country's north, where since Tuesday there have been raging battles between the army and deserters, who refuse to fire on protesters.

The Observatory, citing a local activist, said an army officer was shot dead outside his home by pro-regime gunmen "for refusing to go to Rastan as ordered."

It said 32 soldiers were wounded in clashes overnight in Rastan and Talbisseh.

The Observatory said a young demonstrator was killed Friday in the city of Homs, capital of the province, during one of the marches, which were held under the slogan "victory for our Syria and our Yemen."

There were calls for the downfall of the the hardline regime of President Bashar al-Assad and solidarity with the people of Rastan.

Rights activists also reported protests in a string of other towns and cities, including 10,000 people in Palmyre in central Syria as well as thousands who poured of of mosques to stage demonstrations in Hama, also in the centre, Idlib in the northwest and Zabadani, 40 kilometres (25 miles) north of Damascus.

Security forces opened fire to disperse many of the protests, the activists said, without being able immediately to give an indication of other casualties.

Security forces had shot dead four people, one a young girl, late on Thursday, the watchdog said, while two more civilians including a child were killed in Rastan.

"People seriously wounded in Rastan were unable to receive medical care because of the continuing military operations," the Observatory said.

The latest deaths come after US Secretary of State Hillary Clinton demanded Damascus "take every possible step" to protect American diplomats following a bid by Assad's supporters to attack the US envoy on Thursday.

The attempt to storm an office in Damascus where Robert Ford had just arrived came with the UN Security Council divided over whether to threaten Assad's regime with sanctions.

Opposition figure Hassan Abdelazim, whom Ford had arrived to meet, told AFP the mob "tried to break down the door of my office, but didn't succeed" during a siege that lasted two hours.

Clinton said Washington had raised the attempted attack on Ford at "the highest levels" and demanded Syria "take every possible step to protect" US diplomats.

She also spoke of an "ongoing campaign of intimidation" against not only US diplomats but also those from other countries.

Clinton's deputy spokesman Mark Toner said the mob tried to attack Ford and other embassy staff while they visited Abdelazim, damaging US vehicles and "pelting" the visitors with tomatoes.

The Assad regime had earlier accused Washington of inciting "armed groups" into violence against its army.

Divisions over whether to threaten sanctions against Syria for its deadly crackdown on dissent held up Security Council discussions on a resolution on the crisis.

Britain, France, Germany and Portugal insist that any resolution must include at least the threat of sanctions against Assad, but Russia opposes any mention of sanctions in the text.

The office of the UN High Commissioner for Human Rights in Geneva has said the death toll from the Syrian government's bloody crackdown has risen to more than 2,700 since March 15.

Meanwhile, Sergio Pinheiro, who heads an international commission of inquiry into rights violations in Syria, told reporters in Geneva he hoped to be allowed to visit the country.

"Our hope is that the Syrian Arab Republic will cooperate and give us access to different authorities, and visit different locations," he said, but later added that "we have not yet met the Syrian authorities" to request the visit.