Some 350,000 children are trapped in western Mosul, Save the Children warned on Sunday as Iraqi forces launched an offensive on jihadists in the city.

"Iraqi forces and their allies, including the US and UK, must do everything in their power to protect children and their families from harm, and avoid civilian buildings like schools and hospitals as they push deeper into the city," said the London-based charity's Iraq country director, Maurizio Crivallero.