US Secretary of State John Kerry urged Syrian government forces to stop bombarding the city of Aleppo as it moves in to retake it, Fox News reported.

Kerry said the priority was "a durable, nationwide cessation." The UN envoy for Syria and the lead opposition negotiator have urged the US and Russia to step in and take control of peace talks as a fragile truce hangs in the balance.

The truce between Syrian President Bashar Assad and the US-backed moderate rebels was called in February with the help of the US and Russia.

Kerry is planning to talk with UN envoy Staffan de Mistura in Geneva Sunday along with Saudi and Jordanian foreign ministers. Aleppo was left out of the original "cessation of hostilities" agreement that included the Latakia and Eastern Ghouta regions.

Kerry has expressed "deep concern" about Aleppo to de Mistura and Riad Hijab – the chief negotiator for the High Negations Committee.

Source: MENA