Syrians demonstrate against Assad

Government men shot at, tear-gassed and beat some protesters, but there was no immediate sign of shelling, sniper attacks or other actions that would break the ceasefire.

But opposition activists claimed troops had killed three protesters.

The truce is at the centre of international envoy Kofi Annan's plan to stop the bloodshed and start talks to find a political solution.

His spokesman said the plan had been "relatively respected" despite the continued presence of government troops and heavy weapons in cities.

Ahmad Fawzi also said UN observers are set to enter Syria if the security council tells them to.

He said Mr Annan had told the council that government forces must withdraw from heavily populated areas.

"Violence in all its forms, including arbitrary arrests, torture and abductions, must stop," he added.

Mr Fawzi said the advance team would pave the way for a 250-strong mission that would help keep the peace "if the ceasefire holds and it turns into a genuine cessation of hostilities."

The Britain-based Syrian Observatory for Human Rights estimated that tens of thousands of protesters went out into the country's streets today to demand President Bashar Assad step down.

It claimed one marcher was killed in the opposition stronghold of Hama as he and others tried to reach the main square, which protesters occupied for several weeks last year.

And local activist Adel al-Omar said that two others were killed and 11 wounded in the southern town of Nawa.

Fighting between troops and gunmen was reported near the border with Turkey today, as well as other scattered violence.