GENEVA - Twenty-one patients have died since Israeli Defense Forces raided Al-Shifa, the largest hospital in Gaza, for a second time on March 18, head of the World Health Organization (WHO) said on Sunday.

"Hostilities continue around the hospital," WHO Director-General Tedros Adhanom Ghebreyesus wrote on X, formerly Twitter, citing a health worker inside Al-Shifa.

Over 100 patients, including four children and 28 critical patients, were stranded inside the hospital, lacking necessary means of care. "Many have infected wounds and are dehydrated," said Tedros.

Israeli troops, which launched the latest raid on the hospital in mid-March, said in a statement that they were continuing precise operations in the Al-Shifa hospital to thwart terrorism.

The WHO chief expressed concern over the worsening condition at the hospital, saying contagious diseases were spreading due to extremely poor sanitation and a lack of water.

"Food is extremely limited -- this is potentially life-threatening for diabetic patients whose condition is worsening," he warned.

The UN health agency urged Israel to facilitate access and a humanitarian corridor, so it can carry out lifesaving transfer of patients.