Russia has announced a 48-hour ceasefire for Syria's war-torn Aleppo starting Thursday.

Russia also says the enforcement is to reduce violence and stabilize the situation. A ceasefire was still in place in Damascus' suburb Daraya. Just hours before Russia's announcement, US Secretary of State John Kerry said Russia and the Syrian government should respect a truce agreed in February.

Dozens of fighters were killed in a fresh bout of fighting between Syrian forces, rebels, and jihadists in Aleppo city on Wednesday.