Hundreds of Hamas and Islamic Jihad fighters were arrested by Israeli forces, including several security officials and military commanders, during a wide-ranging raid on Gaza’s Al-Sifa hospital, the army spokesman said.

Israeli troops entered al-Sifa hospital in Gaza in the early hours of Monday and are operating inside the massive complex, which the military says is connected to a tunnel network used as a base for Palestinian militants.

The Israeli military says troops have killed hundreds of militants and captured more than 500 suspects, including 358 members of the Islamist groups Hamas and Islamic Jihad, the highest number since the start of the war.

Daniel Haggari, the Israeli military spokesman, said special forces units had used “deception tactics” to surprise the militants and had inflicted heavy damage on Hamas and Islamic Jihad.

Those arrested included three senior Islamic Jihad military commanders and two Hamas officials responsible for operations in the occupied West Bank, as well as other Hamas internal security officials.

“Those who did not surrender to our forces fought against our forces and were exterminated,” Hagari told a briefing late Thursday.

There was no immediate comment from Hamas or Islamic Jihad.

Al Shifa, the largest hospital in the Gaza Strip before the war, is now one of the few health care facilities even partially functioning in the northern part of the territory, and it also houses displaced civilians.

Hamas and medical staff deny the hospital is being used for military purposes or to shelter militants.

In recent days, Hamas spokesmen said the dead announced in earlier Israeli statements were not fighters but sick and displaced people and accused Israel of war crimes.