MOSCOW (Reuters) - Russian Defence Minister Sergei Shoigu said on Thursday the Russian and Syrian militaries would start a large-scale humanitarian operation in Aleppo during which civilians and militants would be given the chance to leave the city.

Shoigu spoke a day after the Syrian army said it had cut off all supply routes into eastern Aleppo and the government air-dropped leaflets there, asking residents to cooperate with the army and calling on fighters to surrender.

"On behalf of the President of the Russian Federation, today, (we will) start a large-scale humanitarian operation together with the Syrian government to help civilians in Aleppo," Shoigu said in televised comments.

He said three safe corridors would be established by the Russian and Syrian militaries for civilians to leave what was once Syria's largest city, but which is now divided between rebel-controlled and government-held sectors.

Shoigu complained that the military had received no information from the United States on Nusra Front and Free Syrian Army locations in Aleppo and would therefore open a fourth corridor for militants in the north of the city and near the Castello road.

Shoigu also offered militants the chance to surrender, saying Russia had urged the Syrian government to pardon those who have not committed serious crimes.

(Reporting by Alexander Winning; Writing by Maria Tsvetkova; Editing by Andrew Osborn)