Zeid Ra’ad Al Hussein called on all sides to protect civilians.
Mr Zeid expressed shock at a coalition air strike on a camp for internally displaced people in northern Yemen on Monday, which left at least 19 dead.
He also condemned attacks by rebels and allied army units on three hospitals.
The UN says at least 93 civilians have been killed since the 10-nation coalition launched an air campaign five days ago.
The coalition says it intends to “protect and defend the legitimate government” of President Abdrabbuh Mansour Hadi.
Mr Hadi fled abroad last week after the Zaidi Shia rebels advanced on the city of Aden, where he had taken refuge after the Houthis took full control of the capital Sanaa in January and placed him under house arrest.
https://www.endtime.com/wp-content/uploads/2017/06/82035943_82035937.jpg 371 660 alphatimes https://endtime.com/wp-content/uploads/2020/06/endtime-logo.png alphatimes2015-04-01 00:00:002018-03-28 15:39:57Yemen on verge of total collapse, UN human rights chief warns