Russia is ready to discuss a possible ceasefire in Syria, an official said on Thursday, before a crucial meeting of major powers in Germany on how to end the five-year-old Syrian civil war.

"We are ready to discuss the modalities of a ceasefire in Syria," Gennady Gatilov, the deputy foreign minister, was cited by the TASS news agency as saying. "This is what will be talked about in Munich."

Citing an unnamed Western official, the Reuters news agency reported late on Wednesday that Russia proposed a ceasefire to begin on March 1.

International powers, including Russia, the United States, Saudi Arabia and Iran, were to meet on Thursday in Germany in an effort to resurrect Syrian peace talks in Geneva that were postponed earlier this month.

A Syrian government offensive around the city of Aleppo - backed by Russian air strikes - has sent tens of thousands of people fleeing to the Turkish border, putting the Geneva talks in jeopardy.

Al Jazeera's Rory Challands, reporting from Moscow, said that the US and its allies would probably view Russia's truce offer with scepticism.

"The US concerns are that this gives the offensive that's currently ongoing in the Aleppo region more time to push the rebels back, possibly going so far as a full military victory," said Challands.

Meanwhile, the Russian defence ministry lashed out at the US-led coalition in Syria for refusing to provide intelligence on Islamic State of Iraq and the Levant (ISIL) targets there.

Major-General Igor Konashenkov, the defence ministry spokesman, said in a statement on Thursday that Russia has shared its own intelligence with the US which has "gratefully taken" it - but has not reciprocated.

Konashenkov said Moscow has repeatedly asked Washington and its allies for intelligence in response to the accusations that Russians are targeting the "wrong objects".

At least 50,000 Syrians have fled the fighting in Aleppo, the International Committee of the Red Cross said on Wednesday, adding that water supplies have been disrupted in some parts of the province.

The UK-based Syrian Observatory for Human Rights reported on Wednesday that at least 500 people had been killed since the Syrian government, backed by Russian air strikes, launched a major offensive from the north of Aleppo on February 1.

The Observatory said that among those killed were "89 civilians, including 23 children, 143 pro-government fighters, 274 rebels and foreign fighters".

Russian air strikes that began in September have tilted the war in favour of President Bashar al Assad's forces.

The Syrian government holds the west of Aleppo, Syria's largest city, while the rebels hold the east, but the situation is largely reversed in the countryside.

WATCH: Will Syria's war be won or lost in Aleppo?

The latest diplomatic efforts to end the Syrian conflict through peace talks were suspended in Geneva earlier this month until February 25, after UN envoy Staffan de Mistura said that more work was needed to make progress.

The Syrian opposition has said that it will not attend the scheduled talks unless the government ends its air strikes and lifts the sieges on cities and towns.

The peace talks are meant to develop a "road map" to end the conflict of almost five years which has resulted in more than 250,000 Syrians being killed.

The conflict has also displaced millions more and sent hundreds of thousands fleeing as refugees to Europe.