A major conference is being held in Tunisia to seek a breakthrough in the increasingly bitter Syrian unrest.
The US, Europe and Arab countries plan to challenge President Bashar al-Assad to provide humanitarian access within days to the worst-affected areas.
But Russia and China, key allies of Syria which have blocked UN resolutions again Damascus, are not attending the “Friends of Syria” conference.
Activists say more than 90 people died across Syria on Thursday.
Around 70 nations, including the US, UK, France and Turkey are attending the conference, organised by the Arab League.
The conference will agree a declaration on Syria, expected to demand an immediate ceasefire and humanitarian assessment, with the threat of further sanctions if ignored.
The declaration may also boost the standing of the main opposition umbrella group the Syrian National Council, by naming it as a “legitimate” representative of Syrians, but stopping short of giving it full endorsement.
The BBC’s Jonathan Marcus in Tunis says the conference has been conceived as a means of getting around the blocking tactics of Russia and China at the United Nations.
Both countries are considered crucial allies of Damascus and have faced Western and Arab criticism for vetoing a UN Security Council resolution that would have backed an Arab League peace plan for Syria.
They have said they want to see an end to the violence but oppose any international action which amounts to forced regime change.
China said it wanted to “play a constructive role” in the crisis but that international efforts should focus on alleviating tensions, promoting peace and stability and “dissolving differences”.
On the eve of the conference, the UN and Arab League appointed Kofi Annan as their envoy to Syria.
Mr Annan, a former UN secretary general, has in recent years acted as a diplomatic troubleshooter in several long-running conflicts.
He said he was “honoured” to accept the role and looked forward to working with all relevant parties to “help bring an end to the violence and human rights abuses, and promote a peaceful solution to the Syrian crisis”.
US Secretary of State Hillary Clinton said she wanted to see progress on three fronts – providing humanitarian relief, increasing pressure on the regime and preparing for a democratic transition of power.
“To that end, we hope to see new pledges of emergency assistance for Syrians caught in Assad’s stranglehold, and international co-ordination and diplomatic pressure on Damascus to allow it to get to those who need it most. We also expect additional nations to impose effective sanctions against the regime,” she said.
The UK Prime Minister David Cameron said it was vital that the international community came together on the issue of Syria, while French Foreign Minister Alain Juppe said the conference needed to exert the maximum pressure on the Syrian government and also on Russia.
