Israeli strikes on Nasser Hospital in Gaza on Monday killed at least 15 people, including three journalists, one of whom worked for Reuters, Palestinian health officials said. One of the journalists killed in the strikes was cameraman Hussam al-Masri, according to the officials. He was a contractor for Reuters.

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

Among the victims was Mariam Dagga, a freelancer for the Associated Press. Al Jazeera confirmed that its journalist Mohammed Salam was also killed in the strike. Reuters reported that its contractor cameraman Hussam al-Masri was killed,