Thousands of Syrians marched on Friday to test the regime's commitment to a UN-backed peace plan, and the fragile two-day old ceasefire was again shaken when security forces killed eight civilians.
The hard-won truce to end a 13-month crackdown on dissent that has cost an estimated more than 10,000 lives appeared to be holding, but French President Nicolas Sarkozy said he did not expect it to last. He questioned President Bashar al-Assad's sincerity and appealed for observers to monitor his compliance.
UN-Arab League peace envoy Kofi Annan, who brokered the ceasefire, urged Syria to allow humanitarian access to deliver aid.
"Mr Annan is aware that we don't have a perfect situation in the country at the moment," his spokesman Ahmad Fawzi said. "There are detainees that need to be released," Fawzi said, and "humanitarian access" is needed.
Protesters rallied in the Qadam and Assali districts of Damascus, while other demonstrations took place in Irbin and Bibla outside the capital, according to videos posted on the Internet.
The Syrian Observatory for Human Rights said demonstrations were organised across the country, with tens of thousands taking to the street, mostly after the main weekly Muslim prayers.
"The numbers this time are higher than previous weeks," said Observatory head Rami Abdel Rahman.
Sporadic clashes broke out between troops and rebels at Khirbet al-Joz on the border with Turkey, the Observatory said.
Violence on Thursday killed at least 10 people, including seven civilians, and wounded dozens more.
Even so, the toll is markedly lower than in recent weeks, when there have often been scores of people killed on a daily basis.
On Friday, security forces killed six civilians in various cities around the country, and two soldiers lost their lives.
After the ceasefire came into force at dawn on Thursday, Annan declared he was "encouraged by reports that the situation in Syria is relatively calm and that the cessation of hostilities appears to be holding."
But as Assad's government and the rebels traded accusations of trying to wreck the ceasefire, Annan insisted "all parties have obligations to implement fully the six-point plan."
The plan, to which Damascus has committed itself, calls for the withdrawal of forces from urban areas, the release of arbitrarily detained people, freedom of movement for journalists and the right to demonstrate.
Despite the regime's commitment, the spokeswoman for the opposition Syrian National Council (SNC), Basma Qoudmani, said "we have concrete proof that heavy weapons are still in population centres."
The SNC, the most widely recognised opposition group in exile, and Internet-based activists called for peaceful demonstrations to test the government's readiness to accept public shows of dissent.
"We call on the people to demonstrate and express themselves... The right to demonstrate is a principal point of the plan," SNC head Burhan Ghalioun told AFP.
Qoudmani said: "The real test (of the ceasefire) will be if there is shooting or not when people demonstrate."
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The Syrian Revolution 2011 activist group called on Facebook for protests on Friday -- the Muslim day of rest when the demonstrations have been the largest after noon prayers -- under the rallying cry: "A revolution for all Syrians."
But the interior ministry insisted people wanting to demonstrate must have permits.
"The right to demonstrate peacefully is guaranteed by law. We call on citizens to apply the law by requesting a permit before demonstrating," it said.
It had been thought that the UN Security Council might vote Friday on a resolution authorising the deployment of observers to monitor both sides in a conflict the Observatory says has cost more than 10,000 lives.
But Western nations and Russia put forward rival resolutions on Friday, which means that no vote is likely until Saturday.
The Britain, France, Germany and the United States have registered one text for a vote, demanding "full, unimpeded, and immediate freedom of movement" for the monitoring mission.
It also demands that Assad "implement visibly" the commitments he made to Annan, including the withdrawal of troops and weapons from cities.
Annan has said the government has not yet carried out a promise to pull troops and weapons out of "population centers."
The text would force the council to "consider further measures" if Syria does not carry out its commitments.
Russian Ambassador Vitaly Churkin said his mission had put forward a much shorter text, saying the Western countries were putting too much detail into the text.
Details were not immediately released, but diplomats said it did not demand the same level of security guarantees or that Assad pull back troops.
Western nations also want the resolution to condemn "the widespread and gross violations of human rights and the use of force against civilians by the Syrian authorities."
The draft says the council "expresses its intention to consider further steps in the event of non-implementation of relevant commitments."
The UN is planning to send at least 200 monitors to Syria if the tense ceasefire in the country holds.
In other developments, Turkey, which is hosting around 25,000 Syrian refugees, Foreign Minister Ahmet Davutoglu said international aid has begun to arrive.
"We will start getting international aid, and in fact we have already started," he told reporters in Istanbul.
The United Nations High Commissioner for Refugees (UNHCR) this week sent 1,500 tents and 1,500 blankets to Turkey, diplomatic sources told AFP.
On Tuesday, Prime Minister Recep Tayyip Erdogan called on the international community to help Turkey house Syrian refugees.
In the same vein, France said it was considering sending aid for tens of thousands of Syrians refugees in Jordan.