Trapped civilians and rebels are waiting to leave east Aleppo in Syria after a new deal was reportedly reached for evacuations to resume.

Government and rebel sources say the agreement will allow people to leave several besieged enclaves in Syria.

But hours after the announcement, aid agencies were still waiting for the process to start.

At least 6,000 people left east Aleppo under a fragile truce on Thursday, but the operation was halted a day later.

The area has seen rapid government advances in recent weeks.

As well as east Aleppo, the deal is also said to include the evacuation of two other rebel-held towns and two towns loyal to the government.

Only when Shia civilians are allowed out of the pro-government towns of Foua and Kefraya, both besieged by rebels, will Aleppo's convoys begin moving again, reports the BBC's Quentin Sommerville in Istanbul.

Fifty buses have headed to Foua and Kefraya in anticipation, and more are gathering at the Ramousseh crossing outside Aleppo, our correspondent says.

Confusion reigned on Friday morning when the evacuation from east Aleppo, which was taking place along corridors out of the city towards rebel-held areas (Khan al-Asal and Khan Touman), was stopped.

The government said rebel fighters had fired on the convoys at the checkpoint at Ramousseh. Rebels said pro-government forces opened fire.

What happens next?

The United Nations Security Council is expected to vote over the weekend on a French-drafted proposal to ensure the operation is co-ordinated by international observers, with humanitarian aid allowed into Aleppo and hospitals given protection.

Correspondents say thousands of cold and hungry civilians remain stranded in the rebel-held east of the city, waiting to be moved to safety.

The International Committee of the Red Cross (ICRC) called on all sides to provide guarantees and allow the evacuation to be completed.

"It's important that the parties on the ground do their utmost to end this limbo," ICRC Syria head Marianne Gasser said in the statement.

"People have suffered a lot. Please come to an agreement and help save thousands of lives."

Monitoring group the Syrian Observatory for Human Rights said the evacuation from Foah and Kefraya, which are home to some 20,000 people, was expected to start on Saturday.

Syrian state TV, meanwhile, said starting the Idlib evacuations was the main condition for allowing the Aleppo exodus to continue.

Who is still trapped in eastern Aleppo?

The UN's children's charity Unicef says sick and wounded children are among the evacuees from east Aleppo, some of whom left without their parents.

"However, hundreds of other vulnerable children, including orphans, remain trapped inside that part of the city," it added.

"We are extremely concerned about their fate. If these children are not evacuated urgently, they could die."

Abdulkafi al-Hamdo, a teacher who is also still in east Aleppo with his young daughter, told the BBC by phone he did not want to leave his home and city but believed he had no choice.

"The weather is so cold," he said. "Some people have been here since 09:00 yesterday (07:00 GMT on Friday) and the children are so hungry they are crying. They are freezing. Most of them here are scared of a brutal end to the ceasefire.

"They are afraid that they will not be able to get out. This is the feeling of most people here."