Israeli forces have detained hundreds of Hamas and Islamic Jihad fighters including a number of security officials and military commanders during its extended raid into Gaza’s main hospital, the military’s main spokesperson said.

Israeli troops entered the Al Shifa Hospital in Gaza City in the early hours of Monday morning and have been combing through the sprawling complex, which the military says is connected to a tunnel network used as a base for Palestinian fighters.

It says troops have killed hundreds of fighters and detained over 500 suspects, including 358 members of the Islamist militant groups Hamas and Islamic Jihad, the largest number since the beginning of the war nearly six months ago.

Rear Admiral Daniel Hagari, Israel’s main military spokesperson, said special forces units had used “deception tactics” to surprise the fighters and had severely damaged Hamas and Islamic Jihad.

Among the detainees were 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 eliminated,” Hagari told a briefing late on Thursday.

There was no immediate comment from Hamas or Islamic Jihad.

Al Shifa, the Gaza Strip’s biggest hospital before the war, is now one of the few healthcare facilities even partially operational in the north of the territory, and had also been housing displaced civilians.

Israel faced heavy criticism last November when troops first raided the hospital. The troops uncovered tunnels there, which they said had been used as command and control centres by Hamas. Hamas and medical staff deny that the hospital is used for military purposes or to shelter fighters.

In recent days, Hamas spokespeople have said that the dead announced in previous Israeli statements were not fighters but patients and displaced people and have accused Israel of war crimes.

Reuters has been unable to access the hospital and verify either account.