A wave of Israeli strikes across Gaza on Sunday hit a hospital and other sites, killing at least 21 people, including children, as Israel vowed to expand its security presence in the small coastal strip, Associated Press reported.

The predawn strike on Al-Ahli Hospital in Gaza City was the latest of several attacks on northern Gaza’s last major hospital providing critical health care.

Hospital director Dr. Fadel Naim said the emergency room, pharmacy and surrounding buildings were severely damaged, affecting over 100 patients and dozens of staff.

One patient, a girl, died during the evacuation following an Israeli warning because staff were unable to provide urgent care, Gaza’s Health Ministry said. Israel said it struck a Hamas command and control center at the hospital, without providing evidence. Hamas denied the allegations, according to Associated Press.

Al-Ahli Hospital is run by the Episcopal Diocese of Jerusalem, which condemned the attack, saying in a statement it happened on “Palm Sunday, the start of the Holy Week, the most sacred week of the Christian year.”