An emergency meeting of foreign ministers of the UN Security Council member-countries is set to discuss the deteriorating situation in Syria.
The 15-member council, however, is deadlocked over taking strong action after Russia and China blocked three resolutions that criticised Bashar al-Assad, Syria's president, and threatened sanctions.
France, which is council president for August, hopes the body could unite to deal with the aid crisis and convened Thursday's meeting, which will also be attended by ministers from Syria's neighbours Turkey, Lebanon and Jordan.
But less than half the council members are sending ministers, and of the permanent members - the US, China, Russia, Britain and France - only the French foreign minister, Laurent Fabius, and his British counterpart, William Hague, will attend.
No further action
Diplomats said that aside from possible announcements of aid initiatives by individual countries on Thursday, there would be no further action on Syria from the Security Council.
"We wanted a resolution on humanitarian issues, but we faced a double refusal," a French diplomatic source said.
"The United States and Britain believe we have reached the end of what can be achieved at the Security Council, and Moscow and Beijing said that such a resolution would have been biased."
In-depth coverage of escalating violence across Syria
The decision by Hillary Clinton, US secretary of state, to miss Thursday's meeting highlights the US view that with Russia standing by Assad, there is little value in further talks.
France decided to hold the ministerial meeting anyway as a "call to the international conscience and a plea to mobilise humanitarian issues without neglecting the political aspect".
Kofi Annan, who served as the UN and Arab League Syria mediator, blamed the Security Council impasse for hampering his six-month bid to broker peace and leading to his decision to step down.
He will be replaced on Saturday by Algerian diplomat Lakhdar Brahimi.
Brahimi met informally with the Security Council on Wednesday and his spokesman, Ahmad Fawzi, said he has been in "listening mode" while he works out how to approach the Syria conflict.
Opposition fighters said on Thursday that they had shot down a MIG fighter jet and captured its two pilots in Idlib province.
On Wednesday, air and ground bombardments by Syrian forces killed at least 27 people in neighbourhoods on the eastern edge of Damascus, the capital, opposition activists said.
More than 200,000 Syrians, and as many as 300,000, according to some aid groups, have poured out of Syria since the uprising against Assad's rule began last year, while up to three million are displaced.
Turkey, which has seen the highest refugee influx, wants a solution to the problem.
Ahmet Davutoglu, Turkish foreign minister, urged the UN earlier on Wednesday to protect displaced Syrians inside their country, but Assad dismissed talk of a buffer zone.
In a television interview on a privately owned but pro-government Al Dounia channel, Assad on Wednesday said: "Talk of buffer zones firstly is not on the table and secondly it is an unrealistic idea by hostile countries and the enemies of Syria."
He admitted the struggle to defeat opposition forces was difficult, but appeared to be preparing the public for a long battle.
The interview was the second time Assad has appeared on television this month after a six-week absence in the wake of a deadly July bombing that struck his inner circle of top security advisers.