UN envoy to Syria Staffan de Mistura says Damascus is prepared to suspend its aerial bombardment of Aleppo for six weeks for a trial ceasefire, the BBC reports.
Mr de Mistura said the Syrian pledge offered a glimmer of hope although it is unclear when it would take effect.
The opposition Syrian National Council says the government will be judged by actions rather than words.
Government forces have been engaged in heavy fighting as they try to cut a crucial rebel supply route.
More than 100 soldiers and rebels were reported to have been killed on Tuesday as the army captured several villages north of the city.