Ten children have been killed and more than 20 injured by an air strike on a school in Yemen carried out by the Saudi-led military coalition, residents and aid agencies said on Saturday.

Coalition aircraft bombed the small village school in Sa'ada province early on Saturday morning as children on their summer holidays were gathering for religious lessons.

Medecins Sans Frontieres (MSF) said that ten children were killed by the blast and another 28 injured in the attack. All the victims were between eight and 15 years old, the group said.