At least 11 people were killed and more than 19 were injured Monday in an airstrike on a hospital in northwestern Yemen, Doctors Without Borders (MSF) said in a statement.

The blast "partially destroyed" Abs hospital, immediately killing nine people, including an MSF staff member, while two more patients died while being transferred to another clinic, the Paris-based agency said. It expressed outrage at what it described as "the fourth attack against an MSF facility in less than 12 months."