A banner draped across a Damascus home in support of the government [Photo: Cajsa Wikstrom]

Anti-government protesters have taken to the streets of the Syrian capital Damascus for a second day running but their demonstration was quickly quashed by security forces, witnesses said.

Around 100 people, mainly relatives of political prisoners, gathered in Marjeh Square on Wednesday calling for the release of their loved ones and an end to emergency laws.

Government supporters and police armed with batons urged the demonstrators to go home, before arresting four people, witnesses told the Reuters news agency.

On Tuesday some 40 to 50 people gathered after midday prayers in the Al Hamidiya area near the city's Umayyad Mosque in a rare show of dissent against Bashar al-Assad's regime.

Al-Assad, who succeeded his father as president in 2000, has said there is no chance of unrest elsewhere in the region spreading to Syria. The country has been ruled by al-Assad's Baath Party since 1963.

A YouTube video purportedly showing Tuesday's protest showed dozens of people clapping and chanting "God, Syria, freedom -- that's enough", and "Peaceful, peaceful", a chant heard elsewhere in weeks of protests that have swept through the Arab world.

A voice in the background says: "The date is (March) 15 ... This is the first obvious uprising against the Syrian regime ... Alawite or Sunni, all kinds of Syrians, we want to bring down the regime".

The protest was quickly broken up by government supporters, the AP news agency reported.

A Facebook page in favour of a "Syrian revolution" has amassed about 42,000 fans, promoting demonstrations "in all Syrian cities".