A cancer clinic in the Yemeni city of Taiz was hit by heavy weapons on Saturday, with one staff member injured, medical charity Doctors Without Borders (MSF) said, Reuters reports.
The Saudi-backed Yemeni government blamed the attack on the Houthi movement, which has been fighting it since 2014.
There was no comment from the Houthis.
Patients were relocated and non-essential staff sent away, MSF said, after the attack on the clinic which is adjacent to a hospital that the charity supports.
There was also shelling near another hospital which receives its support, MSF said, with two civilians injured.
The Houthis seized Yemen's capital Sanaa and much of the north in 2014. Fighting escalated in March 2015 when the Saudi-led coalition intervened to restore the government of President Abd-Rabbu Mansour Hadi.