Eight soldiers were executed in the Syrian capital Damascus on Friday for refusing to fire on protesters, activists have claimed.

The Local Co-ordination Committees (LCCs), which monitor demonstrations in the country, said the soldiers were killed in the Kesweh area of the capital after a dispute at their barracks. Six people were injured, some of them critically, when security forces fired on demonstrators, the LCCs said.

Analysts say the number of soldiers defecting from the Syrian army seems to be increasing, but this poses little threat to President Bashar al-Assad's regime because there is no sign of senior figures deserting or heavy weaponry being lost. Army attacks on mosques in Hama and Deir Ezzor seem to have been the catalyst for some of the desertions.

Elsewhere, two civilians were killed in the central city of Homs and Idlib province near the Turkish border as security forces fired on protesters across the country when demonstrations followed Friday prayers.

Murhaf Jouejati, a Syria expert at the National Defense University in Washington DC, said the protests in Homs seemed "far larger than usual" and the pro-Assad militiamen, known as Shabiha or "ghosts", had descended on the town in large numbers.

Most foreign journalists are banned from Syria and it is impossible to properly verify what is happening in the country.

Security forces were reported to have broken up a demonstration in another part of Damascus using pump-action shotguns and teargas, and a new video emerged purporting to show a mass grave in the capital.

Protesters have been increasingly calling for international protection from the Assad regime's crackdown as the death toll tops 2,200.

The uprising began six months ago with modest calls for reform and an insistence that there be no foreign intervention such as the Nato operation that helped topple the government of Libya. But now protesters have called for observation missions and human rights monitors to help deter attacks on civilians.

The calls are a sign of the growing frustration – and desperation – by a remarkably resilient movement that has nonetheless failed to bring down Assad, who still has the iron loyalty of the armed forces, which is key to his power.

Widespread international condemnation and sanctions have done little to stop the crackdown. The regime has all but sealed off the country to foreigners, saying the unrest is being driven by terrorists and thugs who want to destroy Syria.

The media blackout makes it difficult to independently confirm reports, but amateur video and other witness accounts have become vital lines of information.

On Friday, videos showed crowds in flashpoint areas, including Damascus, Homs and Idlib, calling for Assad's execution and hoisting signs that read: "Bashar: Game Over!"

Security forces broke up most gatherings by firing bullets and teargas or chasing protesters with batons, activists said.

Several people were killed, but the death toll was not immediately clear.

On Thursday, a leading human rights group said Syrian security forces "forcibly removed" patients from a hospital and prevented doctors from reaching the wounded during a military siege in Homs this week.

The New York-based Human Rights Watch cited testimony from witnesses, including doctors. "Snatching wounded people from the operating room is inhumane and illegal," said Sarah Leah Whitson, its Middle East director.

"Cutting people off from essential medical care causes grave suffering and perhaps irreparable harm."

Wednesday's military operation in Homs killed at least 20 people. It was among the most severe crackdowns on an urban centre during the uprising.

A doctor at the al-Barr hospital told Human Rights Watch that security forces seized some of the wounded from the hospital.

"When we tried to help the wounded, the security forces pushed us back, saying these were criminals and rapists," he said. "They were beating the wounded as they moved them out of the hospital."

There have been other reports of security forces targeting hospitals and rounding up the wounded in Syria and in Bahrain, where there have been widespread protests by the Shi'ite majority against the long-ruling Sunni monarchy.

Doctors and nurses who treated protesters during rallies in Bahrain were rounded up in a crackdown that resulted in the arrests of hundreds of activists.