Thousands of Syrians today braved security forces and marched in the southern town of Daraa after the funeral of a protester killed in the previous day's unrest, witnesses said.

Protests also spread to the nearby towns of Jasim and Enkhel, witnesses said.

"There was a massive deployment of security forces (in to block protests but thousands gathered anyway," a witness told AFP adding they used tear gas to break up the crowd and "arrested several people" on the fourth day of unrest.

Daraa has become the unexpected nerve centre of anti-regime protests in Syria, with protesters holding daily demonstrations since Friday despite a huge deployment of security forces and a heavy-handed crackdown on protests that left five dead.

A mass of demonstrators marched from the cemetery towards Al-Omari mosque after the burial of Raed Akrad, who was killed by security forces Sunday when they opened fire to disperse a protest.

"Just God, Syria and Freedom," and "Revolution, revolution" chanted the demonstrators and an activist told AFP that they would keep up their protests "until all the demands were met."

The protesters, who have been inspired by regime-changing revolts in Tunisia and Egypt, are demanding "freedom" and an end to 48 years of emergency laws in Syria under President Bashar al-Assad and his father Hafez.

Hundreds of demonstrators on Sunday set Daraa's courthouse as well as other buildings a car ablaze, following clashes with police that left one person dead and 100 wounded.

The incident ignited support protests Monday in Daraa's neighbouring towns.

In Enkhel, protesters stormed a police station and in Jasim about 2,000 people demonstrators chanted "peaceful, peaceful" and "Martyr, we will sacrifice ourselves for you," according to an AFP correspondent.

As popular uprisings rock the Middle East and rooted regimes unravel, Syria has shown zero tolerance for protests with the army showing up in Daraa on Monday and soldiers checking the id-card of anyone who entered the town.

Human rights groups said Monday Syrian security forces had unleashed a wave of "arbitrary detentions" and "excessive force" in several cities where anti-regime protests flared in recent days.

"Eleven people were detained Friday after a demonstration outside the Omayyed mosque in Damascus, and several others were arrested in the port city of Banias," said the Syrian Observatory for Human Rights.

On Thursday, 32 protesters who were arrested during a Damascus rally calling for the release of political prisoners faced charges of "attacking the reputation of the state" and "inciting racism and sectarianism."

On Saturday security forces arrested "dozens of protesters" in Daraa, where thousands attended the funerals of two of four people killed on the previous day's violent crackdown, a rights activist said.

The protests followed a call for a "Day of Dignity" across Syrian cities from a Facebook group that has emerged as a major mobilising force since March 15 although previous rallying efforts had fallen flat.

The Syrian Observatory condemned the "politics of arbitrary detentions" and called on the Syrian government to "immediately free all prisoners of conscience."

"The Syrian government has shown no qualms about shooting dead its own citizens for speaking out," said Sarah Leah Whitson, Middle East and North Africa director of US-based Human Rights Watch.

As in Egypt, tough security services -- empowered by emergency laws -- have become a mobilising force with one of the first impromptu protests sparked by police brutality in Old City Damascus mid-February.

"Syrians have shown incredible courage in daring to protest publicly against one of the most repressive governments in the region, and they shouldn’t have to pay with their lives," Whitson said.

Activists said one person was killed Sunday and at least 100 were wounded when security forces fired on protesters who went on a rampage in Daraa on the third consecutive day of demonstrations in the town.

They had reported four deaths in the preceding two days.

A Syrian official denied Sunday's death, accusing "troublemakers" of fuelling unrest as cabinet ministers, dispatched by President Bashar al-Assad, gave condolences to the families of protesters killed in Daraa.

France on Monday condemned the crackdown and called for the release of all detained protesters.