MOSCOW — Russia’s military said Wednesday that fighting in Aleppo will cease for three hours daily to allow humanitarian aid deliveries, but it was unclear whether rebels had agreed. And a United Nations official said a break in fighting for at least 48 hours was needed to get sufficient aid into the city.

Lieutenant General Sergei Rudskoi of the Russian military’s General Staff said cease-fires will be observed from 10 a.m. to 1 p.m. He did not say if the rebels agreed to respect the halts in hostilities, or explain how they would be enforced.

He said Russia supports the UN proposal to oversee the aid deliveries, adding the Russian military is talking with the UN and the US military.

In Washington, the State Department said all parties to the Syrian conflict must abide by the UN request to ensure access for humanitarian supplies.

Rudskoi told a briefing in Moscow that humanitarian convoys will be formed near Handarat and will move on the strategic Castello road. At the United Nations, humanitarian chief Stephen O’Brien said 48 hours and a two-lane road are the minimum needed to get aid into Aleppo. ‘‘When we’re offered three hours, then you have to ask what could be achieved in those three hours?’’