Aleppo hospital hit by Assad regime airstrikes
Aleppo hospital hit by Assad regime airstrikesReuters

Syria's military announced on Wednesday that it is reducing its bombardment of rebels in devastated Aleppo, in a surprise move nearly two weeks after declaring an all-out assault to capture the city, AFP reported.

Once Syria's commercial hub, Aleppo has been divided by rebel groups in the east and regime forces in the west since violence erupted there in 2012.

The military announced the offensive to capture the whole city on September 22, ushering in a ferocious bombing campaign on opposition-held quarters that a monitor says has killed 270 people, including 53 children.

The offensive on Aleppo was announced after a truce deal brokered by Moscow and Washington fell apart.

But on Wednesday, the Syrian army said the bombardment would be reduced "after the success of our armed forces in Aleppo and cutting off all terrorist supply routes into the eastern districts".

"The military command has decided to reduce the number of air strikes and artillery on terrorist positions to allow civilians that want to leave to reach safe areas," said a statement quoted by AFP.

It was not immediately clear what was behind the move, or if Russian air strikes would also be reduced.

The announcement came as Russia's TASS news agency said Foreign Minister Sergei Lavrov and U.S. counterpart John Kerry "exchanged views on Syria" in a telephone call on Wednesday.

Forces loyal to President Bashar Al-Assad have been waging their offensive on the city with the backing of Russian air power.

But the onslaught has come under intense international scrutiny amid accusations it was indiscriminate and devastating civilian infrastructure.

On Monday, bombardment destroyed the largest hospital in rebel-held quarters, where an estimated 250,000 people live under government siege.

Hours later, Washington announced it would halt bilateral efforts with Moscow aimed at reviving a ceasefire, accusing Russia of trying to bomb civilians "into submission".

Despite this, Lavrov and Kerry spoke Wednesday, with the Russian noting the "responsibility for the collapse of the truce lies with the U.S." given its decision to suspend contacts.

But in another sign of increasing tensions, Russia said it was suspending joint research with the United States on nuclear energy projects.

Moscow and Washington's top diplomats had been working together since early this year to reach a diplomatic solution to Syria's bloodshed, which has killed more than 300,000 people since 2011.

An agreement in September had envisioned an end to hostilities, increased aid deliveries, and eventual coordination between the two world powers against jihadists -- but it collapsed after a week.

Since then, France has stepped into the diplomatic vacuum with a draft UN resolution on a truce in Aleppo that it will submit to the Security Council this week.

French Foreign Minister Jean-Marc Ayrault will travel to Moscow on Thursday and Washington on Friday to try to garner support for the draft, his office said.

AFP contributed to this report.