US-Israeli strikes hit one of the leading health research institutions in Iran, a government official said Thursday, as relief agencies warned against mass attacks on medical facilities in the region.

The Pasteur Institute of Iran, one of the “century-old pillars” of global health in the region, was struck in a “direct assault on international health security,” Hossein Kermanpour, head of the information center at the Iranian Ministry of Health, posted on X.

Established in 1920, the institute is the first and oldest public health center in Iran – where staffers pioneered vaccine development and research on the prevention of infectious diseases.

CNN has reached out to CENTCOM and the Israeli military for comment.

More than 30 days of US-Israeli bombing on Iran and retaliatory Iranian strikes on Israel has depleted medical systems and laid waste to entire neighborhoods in Iran and Lebanon, killing thousands of people across the Middle East.

At least 316 health care and emergency centers have been damaged in Iran since February 28, the Iranian Red Crescent reported on April 1. On average, health care systems in Iran, Lebanon and Israel have come under attack about once every six hours, the NGO, Save the Children said on March 31.

Last month, the World Health Organization (WHO) reiterated that health workers, patients and health facilities “must always be protected under international humanitarian law.”

CNN’s Eugenia Yosef contributed reporting.