KABUL - Gunmen dressed as doctors stormed Afghanistan's largest military hospital on Wednesday, officials said, in an attack claimed by the Islamic State group as it makes inroads into the war-battered country.

The assault on the Sardar Daud Khan hospital left at least 30 people dead and more than 50 others wounded, military officials said.

Medical staff hunkered down in the hospital wards posted desperate messages for help on social media, with local television footage showing some of them trapped on the ledge of a top floor window.