The World Health Organization has confirmed “several” attacks on health care centres in Ukraine and is investigating others, the agency’s chief said on Sunday.

The attacks caused multiple deaths and injuries, Tedros Adhanom Ghebreyesus added in a Twitter message.

“Attacks on healthcare facilities or workers breach medical neutrality and are violations of international humanitarian law,” he said.

In his brief post, Tedros did not mention Russia, which invaded Ukraine on Feb. 24.