Mariam Dagga, a freelance visual journalist in Gaza for The Associated Press, was killed by an Israeli strike on a hospital. She was 33.

Israeli Prime Minister Benjamin Netanyahu’s office said the strike on Nasser Hospital was a “tragic mishap” and that the military was investigating.

Israel hit Nasser Hospital with a missile and then fired another as journalists and rescue workers rushed to the scene, killing at least 20 people, local health workers said. Mariam Dagga, 33, who frequently based herself at Nasser during work for The Associated Press and other outlets,