The United Nations is waiting for a promised pause in fighting around besieged rebel-held areas of Syria's third-largest city Homs to deliver desperately needed aid and evacuate civilians who want to leave.
Under a surprise deal struck by the UN on Thursday, the Syrian government agreed to a "humanitarian pause" in the fighting around the rebel-held enclave in the city centre to allow in food and medicines for the hundreds of civilians who have lived under siege for more than 600 days.
The relief supplies had been held up in a UN warehouse in a government-held area of the city just kilometres away while the negotiations for relief access dragged on for months.
Washington said that the aid convoy was expected to enter early Friday, although UN officials cautioned that the timing would depend on the agreed halt to fighting going into effect on the ground.
The rebel-held Old City and adjacent neighbourhoods have come under near-daily shelling since the army imposed a blockade in June 2012 after recapturing most of Homs in a counter-offensive launched that February.
At least 1200 children, women and elderly people are among some 2500 civilians who have been trapped under siege, surviving on little but olives, the Syrian Observatory for Human Rights says.
It was left to UN representatives in Damascus to thrash out the deal with Syrian officials, who had long insisted that they would allow civilians to leave but would not allow aid to be taken in.
State Department spokeswoman Jen Psaki said: "We understand the operations will begin Friday morning, and will include a local humanitarian pause while the evacuations take place and while the food and other humanitarian assistance is delivered."
In Geneva, the UN Office for the Co-ordination of Humanitarian Affairs (OCHA) said food and supplies had been placed on the outskirts of Homs but they would not be delivered until safety is assured.
"You may only hear about the actual delivery when it has taken place. And that is simply to ensure the safety of our staff," OCHA spokesman Jens Laerke said.
In the first year of the uprising against President Bashar al-Assad's rule that erupted in March 2011, activists dubbed Homs the capital of the revolution.
But a bloody counter-offensive launched by the army in February 2012 saw it recapture much of the central city, which lies on a strategic crossroads on highways between Damascus and the north, and the interior and the Mediterranean coast.