SANAA, Yemen (AP) -- The aid group Doctors Without Borders says a projectile from an unknown source has hit a hospital it supports in Yemen's northern Saada province, killing four and injuring 10.
The group, known as MSF, says in a statement that the Sunday attack in the Razeh district led to "the collapse of several buildings of the medical facility."
Of those injured at the Shiara Hospital, three are MSF staff, and two are in critical condition, it said. All staff and patients have been moved to another hospital also supported by MSF.
"The numbers of casualties could rise as there could still be people trapped in the rubble," the group said.
"All warrying parties are regularly informed of the GPS coordinates of the medical sites where MSF works," said Raquel Ayora, the group's director of operations. "There is no way that anyone with the capacity to carry out an airstrike or launch a rocket would not have known that the Shiara Hospital," was an MSF-supported medical facility.
MSF operates in eight Yemeni provinces at a time when many foreign aid groups and even United Nations personnel have been evacuated. It has been working at the impacted hospital since November. The group said this was the third "severe incident" in a health facility it supports in Yemen.
Shiite rebels known as Houthis took over the capital, Sanaa, in September 2014; in March 2015, a Saudi-led coalition started launching airstrikes against Houthi and allied forces' positions.
Saada, a Houthi stronghold, has faced a particularly intense bombardment.