Calm has prevailed across the divided Syrian city of Aleppo on the third day of a unilateral ceasefire announced by Russia.
However despite the calm, medical evacuations and aid deliveries have yet to take place, a war monitor and the United Nations say.
No Syrian or Russian air strikes on the eastern rebel-held side of Aleppo have been reported since Russia began the pause in hostilities on Thursday, the Syrian Observatory for Human Rights said on Saturday.
But rebels have said they cannot accept the ceasefire, which they say does nothing to alleviate the situation of those who choose to remain in rebel-held Aleppo, and believe it is part of a government policy to purge cities of political opponents.
The Syrian army and Russia have called on residents and rebels in besieged eastern Aleppo to leave the city through designated corridors and depart for other insurgent-held districts under a promise of safe travel, but very few rebels or civilians appear to have left.
"Nobody has left through the corridors. The small number of people which who tried to leave were faced with shelling around the (corridor area) and could not leave," said Zakaria Malahifji, a rebel official with the Fastaqim group, which is present in the city.
Mr Malahifji said shelling and clashes continued at normal levels in parts of the city.
Syrian state media says rebels are preventing civilians from leaving east Aleppo. Pro-government channels broadcast footage of ambulances and green buses parked at empty reception points in government-held Aleppo, said to be waiting for civilians and fighters from the city's east.
Besieged east Aleppo has not received United Nations assistance since early July.
The United Nations had hoped that the ceasefires would allow medical evacuations and aid deliveries, but said a lack of security guarantees and facilitation were preventing aid workers taking advantage of the pause in bombing.
"The UN remains hopeful that parties will provide all necessary guarantees and is actively working to that end," UN humanitarian spokesman Jens Laerke said on Saturday.
"The situation on the ground remains volatile as exchanges of fire and clashes continue. Just today bullets struck the hotel where the UN hub is based and critically injured one hotel staff," Mr Laerke said.
Sporadic clashes between insurgents and Syrian government and allied forces have been reported during the period of calm along frontlines, with some shells falling on both the government-held western side of the city and the rebel-held east, the Observatory said.
Syrian President Bashar al-Assad, backed by the Russian military, Iran's Revolutionary Guards and an array of Shi'ite Muslim militias, wants to take full control of the city.
Kremlin spokesman Dmitry Peskov said on Saturday Russia remains committed to removing what it calls terrorist organisations from Syria and preventing the disintegration of the country.
"A temporary base is not a goal, it's a means to achieve the goal that was declared by the president - to help legitimate Syrian authorities in their fight with ISIS and other terrorist organisations. The Syrian territory must be liberated," MR Peskov said in a television interview.