President Vladimir Putin has ordered a 10-hour truce on Friday in the war-ravaged Syrian city of Aleppo, the Russian defence ministry said.

"A decision was made to introduce a 'humanitarian pause' in Aleppo on November 4 from 9:00 am (0600 GMT) to 19:00," the chief of Russia's General Staff Valery Gerasimov said in a statement on Wednesday.

Gerasimov said the decision was approved by Syrian authorities and was meant to "prevent senseless casualties" by allowing civilians and armed combatants to quit rebel-held eastern Aleppo.

He said eight corridors -- six for civilians and two for fighters -- could be used for this.

Rebels launched a major assault Friday to break the siege of Aleppo but have been met this week by fierce resistance from regime forces.

Aleppo has been hit by some of the worst violence in Syria's five-year conflict, turning the once bustling economic hub into a divided and bombed-out city.

Defence ministry Sergei Shoigu said Tuesday that Russia had ceased air strikes on eastern Aleppo for 16 days, following criticism over a Russian-backed Syrian government assault that has killed hundreds of civilians and destroyed infrastructure, including hospitals.

The halt in bombing was initially declared ahead of a short ceasefire that ended last month. Moscow at the time ruled out a truce extension.

Shoigu accused the US-led coalition of failing to rein in hardline rebels and said that the chances of a political settlement to the crisis was now remote.

The West has accused Moscow of committing possible war crimes in Aleppo through indiscriminate bombing to support a brutal Syrian government offensive.

Moscow has been conducting a bombing campaign in Syria in support of long-time ally Bashar al-Assad since September 2015.

More than 300,000 people have been killed since Syria's war devolved from a widespread protest movement against Assad's rule in March 2011 to a multi-front war between rebels, Islamist militants , Kurds and regime forces.