Syrian artillery hit parts of Homs city and at least 10 people were killed in clashes around the country on Friday, opposition activists said, as peace envoy Kofi Annan told President Bashar al-Assad his forces must be first to cease fire and withdraw.
"The deadline is now," Ahmad Fawzi, Annan's spokesperson, said in Geneva. "We expect him to implement this plan immediately."
In-depth coverage of escalating violence across Syria
An army pullback to bases would permit a safe return to mass, peaceful protest, said anti-government activists. But there was no sign of any risk-free demonstrations on Friday.
Five people were killed as rebels battled the army after troops broke up a protest in Deir al-Zor near the border with Iraq, the Syrian Observatory for Human Rights reported, and protests drew gunfire in several neighbourhoods of Damascus.
"Clashes erupted between armed defector groups and the regime forces in the Jobar neighbourhood of Damascus after security forces tried to break up a protest," the Observatory said.
It also reported government snipers killing two people in the cities of Idlib and Homs. Two were shot dead in southern Deraa, where rebels attacking a checkpoint killed a soldier.
Shelling in Homs
In Homs, Syria's third city, residents said shells and mortar rounds exploded as troops raided anti-Assad areas.
Farther north, many were wounded in fighting in Idlib province. Assad has said he will spare no effort to implement Annan's peace proposals, but warned they would not work unless there is an end to foreign funding and arming of rebel groups.
Jonah Hull reports on how international diplomatic efforts are failing to resolve the Syrian conflict.
The United Nations says Assad's forces have killed at least 9,000 people in the year-long uprising. The government says around 3,000 soldiers and police have been killed.
Removing any ambiguity about the ceasefire terms of the peace plan Assad has said he accepts, Annan's spokesperson said it was up to the Syrian military to move first and show good faith by withdrawing tanks, big guns and troops from cities.
The Annan plan "specifically asks the government to withdraw its troops, to cease using heavy weapons in populated centres", Fawzi said.
"The very clear implication here is that the government must stop first and then discuss a cessation of hostilities with the other side and with the mediator."
The plan requires the lightly-armed rebels to stop shooting.
But the Free Syrian Army (FSA) has not said whether it accepts Annan's proposals and political opposition groups have not explicitly endorsed his call for a dialogue with Assad.
Annan is acting on behalf of the United Nations and Arab League. Diplomats say he may ask for a UN monitoring mission to oversee implementation of the peace plan.
"Let's not get ahead of ourselves. First we want to see that the bloodbath ends," an activist calling himself Abu Mohammed said.
If the UN plan is adopted and peace monitors are deployed, the opposition could protest peacefully and openly as Egyptians did during their revolt against Hosni Mubarak, he said.
"But it's not going to happen."
Hezbollah restates support
Lebanon's Hezbollah movement said on Friday Arab and international efforts to end the conflict in Syria have moved away from demanding that President Bashar al-Assad steps down and now appear focused on achieving political dialogue.
Hezbollah leader Sayyed Hassan Nasrallah, a key Assad ally, also declared in his speech Syrian opposition fighters who have fought a year-long campaign to oust Assad were incapable of toppling him and that the option of foreign military intervention in Syria was a "closed subject".
"Some people talked about the political option ... but with conditions that equalled the fall of the regime, for example for President Assad to step down. I think the international and regional political climate today has passed this phase."
Assad's strongest regional ally, Iran, said 12 Iranian citizens abducted "by Syrian opposition forces" had been released, including five engineers working for Syria's power plant in Homs who were kidnapped in late December.
Iran's state IRNA news agency said Syrian "armed gangs" had kidnapped dozens of pilgrims from Iran. In January, Syrian opposition forces released video of seven men they said were Iranian soldiers captured in Syria.
Iran, meanwhile, is helping Syria beat Western sanctions by providing a tanker to ship Syrian oil to China, netting a potential $80mn. Along with Syria's big-power ally Russia, China has shielded Assad, vetoing two Western-backed resolutions at the United Nations over the bloodshed.
China is not bound by Western sanctions against Syria.
Meanwhile, US secretary of state Hillary Clinton met Saudi Arabia's King Abdullah in Riyadh on Friday to discuss the conflict ahead of a "Friends of Syria" conference with opposition leaders and Arab and Western foreign ministers at the weekend in Istanbul.
Saudi Arabia, with Qatar, has led Arab efforts to press Assad to end his crackdown on the uprising and step aside.