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

Five journalists were among at least 21 people killed in an Israeli airstrike at the Nasser Medical Complex in the southern Gaza city of Khan Younis on Monday.

At least 20 people, including five journalists working for the international media, are said to have been killed in Israeli military strikes on Nasser Hospital in southern Gaza. The Israeli military has confirmed it carried out an attack nearby, but not why the building was hit. It says it’s ordered an initial inquiry.