Syrian forces pressed their assault across the country on Monday as international peace envoy Kofi Annan stressed that there can be no deadline to ending the year-long crisis.
Clashes were reported in the central flashpoint city of Homs, in Damascus province and other areas, leaving at least 32 people dead, including 19 civilians, the Syrian Observatory for Human Rights said.
At least 16 people, among them four soldiers and two children, were killed as regime forces pounded several neighbourhoods of Homs, the Britain-based watchdog said.
In Damascus province, seven soldiers and five civilians were killed in clashes in two towns -- Harasta and Zabadani.
The violence came as Annan, the United Nations and Arab League envoy to Syria, said no time limit could be set to ending the revolt against the regime of President Bashar al-Assad that erupted last March.
"I think only Syrians should decide the issue of Assad's resignation," Annan told Russian news agencies in remarks translated into Russian.
"It's important to sit all Syrians behind a negotiating table," he said, speaking a day after meeting Russian President Dmitry Medvedev.
The former UN chief said it was "incorrect to give any deadlines" for ending the violence in Syria, in which more than 9,100 people have already been killed, according to monitors.
Medvedev warned on Sunday that Annan represented the last chance for avoiding a civil war in Syria, and promised him Russia's full support.
Annan is to hold negotiations on Tuesday with Beijing, which he said he hoped will also support his mission.
Russia and China have vetoed previous resolutions to condemn Assad's regime. But last week they backed a UN Security Council peace plan for Syria put forward by the UN-Arab League envoy.
Annan's plan calls for a halt to fighting, with the government pulling troops and heavy weapons out of protest cities, a daily two-hour humanitarian pause to hostilities and access to all areas affected by the fighting.
It also calls for the release of people detained in the uprising. However it imposes no deadline for Assad to carry out these demands, nor does it call for his resignation.
The former UN chief's spokesman said in a statement Monday that Damascus had responded afresh on the six-point proposal to end the crisis.
"Mr Annan is studying it and will respond very shortly," he said.
Medvedev, whose government has come under increasing pressure to act on Syria, on Monday discussed the crisis in Seoul with US President Barack Obama.
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Afterwards, Obama acknowledged there had been disagreements in the past few months between the United States and Russia, an ally of Assad's regime.
But he said both agreed "we should be supportive of Kofi Annan's efforts to end some of the bloodshed that is taking place in Syria," and that the goal was to have a "legitimate" government in Damascus.
Meanwhile, US Secretary of State Hillary Clinton will visit Saudi Arabia on Saturday and Sunday for talks on Syria, State Department spokeswoman Victoria Nuland said.
Annan is now expected in China on Tuesday to shore up backing for his efforts from the two UN Security Council members that have vetoed previous resolutions to condemn Assad's regime.
Beijing "hopes this visit will allow in-depth discussions on a political resolution of the Syrian issue," foreign ministry spokesman Hong Lei said.
In Ankara, a diplomatic source said a decision by Turkey to close its mission in Damascus was linked to security conditions, a move echoed by Norway.
Meanwhile Syria's fragmented opposition was meeting in Istanbul.
"The aim is for the opposition to agree on a united position and to outline the major points of a national pact," Mohamed Sermini, a member of the Syrian National Council, the main opposition group, told AFP.
The crisis is also expected to dominate an Arab summit in Baghdad this week.
Syria is a "pressing issue... It has an international dimension, it has a regional (dimension)," Iraqi Foreign Minister Hoshyar Zebari told reporters ahead of the summit.
On the ground, security forces launched dawn raids in the eastern hot spot of Deir Ezzor, arresting 16 people, and also staged operations in Daraa province, activists said.
In central Hama, an activist said regime forces raided Kafr Zeita.
"They arrested militants and doctors and burned down their houses," Abu Ghazi, who was reached through Skype, told AFP.
"They have isolated the town by installing checkpoints at all entrances and posting snipers in areas overlooking the town."
And the Observatory said more than 70 percent of the population of Saraqeb in northwest Idlib province has fled over the past 48 hours in the face of a government assault that began on Saturday.
It said at least 18 civilians have been killed there and more than 63 homes torched.