KHAN YOUNIS, Gaza Strip (AP) — Heavy fighting erupted Monday around a hospital in northern Gaza where thousands of patients and displaced people have been sheltering for weeks, as Israeli forces focus on clearing medical facilities that they say Hamas militants use for cover.

A shell struck the second floor of the Indonesian Hospital, killing at least 12 people, according to the Health Ministry in Hamas-ruled Gaza and a medical worker inside the facility. There was no immediate comment from the Israeli military.