Russian Defense Minister Sergei Shoigu says Russia and the Syrian government will open humanitarian corridors and offer a way-out for Islamic State fighters wanting to lay down their arms.

Syrian government forces and allied troops have tightened the noose on the main rebel enclave in the city of Aleppo, urging fighters there to surrender. Humanitarian groups have warned of a major catastrophe if the siege on the rebel-held parts of Aleppo continued.

Shoigu said in televised comments Thursday that President Vladimir Putin has a "large-scale humanitarian operation" that will be launched outside Aleppo to "help civilians who were taken hostage by terrorists as well as fighters who wanted to lay down the arms." Shoigu mentioned three humanitarian corridors as well as food and first aid points outside the city.