(Reuters) -Israeli strikes on Nasser hospital in Gaza on Monday killed at least 15 people, including four journalists, one of whom worked for Reuters, Palestinian health officials said.

Cameraman Hussam al-Masri, a Reuters contractor, was killed in the first strike, according to the officials. Photographer Hatem Khaled, who was also a Reuters contractor, was wounded in a second strike on the hospital, they said.

Witnesses said the second strike took place after rescue workers, journalists and other people had rushed to the site of the initial attack. The Reuters live video feed from the hospital, which was operated by Masri, suddenly shut down at the moment of the initial strike, Reuters footage showed.

"We are devastated to learn of the death of Reuters contractor Hussam al-Masri and injuries to another of our contractors, Hatem Khaled, in Israeli strikes on the Nasser hospital in Gaza today," a Reuters spokesperson said in a statement.

The Israeli military and Prime Minister's Office both had no immediate comment regarding the strikes.

Health officials in Gaza named the three other journalists as Mariam Abu Dagga, who the Associated Press said freelanced for the AP and other outlets since the start of the Gaza conflict, Mohammed Salama, who Qatar-based Al Jazeera said worked for the broadcaster, and Moaz Abu Taha. A rescue worker was also among those killed, the health officials added.

The Palestinian Journalists Syndicate condemned Israel for the strikes, saying it represented "an open war against free media, with the aim of terrorising journalists and preventing them from fulfilling their professional duty of exposing its crimes to the world."

(Reporting by Nidal Al Mughrabi, Editing by Edmund Blair and Timothy Heritage)