At least 18 people were killed and dozens of others wounded in an Israeli airstrike on a Gaza mosque early on Sunday, the Palestinian news agency Wafa reported.
The strike was carried out on the mosque near the Al-Aqsa Hospital in Deir al-Balah in the central Gaza Strip.
Eyewitnesses said the number of casualties could rise as the mosque was being used to house displaced people.
The Israeli military said in a statement it "conducted a precise strike on Hamas terrorists who were operating within a command and control center embedded in a structure that previously served as the 'Shuhada al-Aqsa' Mosque in the area of Deir al Balah."
Israel's military assault on Gaza has killed nearly 42,000 Palestinians, according to Gaza's health ministry. It has also displaced nearly all of the enclave's 2.3 million people, caused a hunger crisis and led to genocide allegations at the World Court that Israel denies.