Russia announced on Wednesday it would give rebels a ten hour window of opportunity to escape the Syrian city of Aleppo.
The rebels have intensified their attacks to break the Syrian regime's siege on east Aleppo, refusing withdrawal from the city during the 10-hour-long “humanitarian pause” in attacks which started at 07:00 GMT on Friday.
"This is completely out of the question. We will not give up the city of Aleppo to the Russians and we won't surrender," Zakaria Malahifji of the Fastaqim rebel group, said on Wednesday.
Russia-backed regime forces ceased air strikes on Aleppo on October 18 after Western governments fiercely criticised the strikes, which killed a large number of civilians and left thousands more trapped in the city.
A cease-fire brokered by Russia and the United States fell apart in September, after which the Syrian regime and Russia stepped up air strikes targeting opposition-held areas in eastern Aleppo.
The Russian Defence Ministry said in a statement that President Vladimir Putin ordered the pause to "prevent senseless casualties" by allowing civilians and combatants out of eastern Aleppo.
According to the statement, rebels will be allowed to leave the city with their weapons safely via two special corridors as civilians will be transferred by six other routes reserved for them.
But the rebels claim that there will not be safe exit corridors.
"It's not true. Civilians and fighters are not leaving. Civilians are afraid of the regime, they don't trust it. And the fighters are not surrendering," Malahifji said.
Formerly Syria's economic powerhouse, Aleppo has been divided since mid-2012 between regime control in the west and rebels in the east.
The city have suffered some of the heaviest fighting in Syria's five-year-long civil war, which has claimed at least 300,000 lives.
Since early July, the more than 250,000 people trapped inside the city have received no aid.