The Israeli military said on Tuesday that its initial inquiry determined that a deadly attack on a Gaza hospital was intended to destroy an observation camera placed in the area by Hamas militants.

The strike on Nasser Hospital in the southern city of Khan Younis on Monday killed 20 people, five of them Gaza-based Palestinian journalists, according to the Gazan health ministry. The office of Prime Minister Benjamin Netanyahu of Israel, in a rare expression of regret, suggested later on Monday that it had been a military blunder.

After an initial internal inquiry, a military statement said troops from the Golani infantry brigade operating in Khan Younis had “identified a camera that was positioned by Hamas in the area of the Nasser Hospital that was being used to observe the activity of Israel Defense Forces in order to direct terrorist activities against them.

The military, citing what it described as “intelligence confirming Hamas’ use of the Nasser Hospital to carry out terrorist activities since the start of the war” in Gaza, said the troops “operated to remove the threat by striking and dismantling the camera.”

The statement did not provide evidence that the camera had been placed there by Hamas, or was being used to monitor troops. Nor did it address evidence, provided by witnesses and video footage, that a first strike was followed minutes later by a second that hit the same part of the hospital after rescue workers and journalists rushed to the scene.

There was no immediate comment from Hamas.

At least some of the journalists were killed in the second strike, along with rescue workers, hospital staff and patients, according to hospital officials.

The military did not specify what kind of munitions were used in the attack and said that the chief of staff, Lt. Gen. Eyal Zamir, had called for further examination of the strike authorization process, including the ammunition approved for the strike.