Israeli forces occupy the Hamas military command center, the hospital complex, in a video message on social media on Monday, April 8

Israel has said that the hospital complex doubled as a secret Hamas military command center, calling it one of many examples of civilian facilities that Hamas uses to shield its activities. The U.S. spy agencies say that the Palestinian group Hamas and others used Al-Shifa to hold captives.

In a video on social media early Monday, Daniel Hagari, spokesman for the Israel Defense Force, said that forces will conduct the operation with care andcaution, while ensuring the hospital continues its important functions.

“Communications were cut off, and the displaced people were trapped inside the specialized surgery building and in the emergency reception in Building 8,” according to the ministry.

There were flyers dropped on top of Al-Shifa, urging people to leave. Locals in Gaza inside the medical complex shared the flyers with the media.

Ms al-Kaas said she heard the sounds of tanks, as well as shots and the sound of people being ordered to stay inside by Israeli soldiers, around the same time. She said Israeli forces told people that they would be moved to the Al-Mawasi area in southern Gaza, although it was not immediately clear when or how they would be moved. Israel sought to create a safe zone in Al- Mawasi for civilians, although they have found little shelter there.

The video statement said that the military of Israel would provide food, water and other supplies to the people on the ground.

Israel came under criticism after storming the hospital in November from health and humanitarian organizations. Evidence examined by The New York Times suggests Hamas did use the hospital for cover and maintained a hardened tunnel beneath it that was supplied with water, power and air-conditioning. The Israeli military is attempting to prove that there was a command and control center under the facility.

Ms. al-Kaas said that she had seen Israeli soldiers holding several people, their hands bound and clothes partially stripped off, in the courtyard of the hospital complex. She added that bodies of people who had apparently been shot were lying in the courtyard.

The hospital was occupied by about 15 Israeli tanks and bulldozers at noon, according to the daughter of one of the people being treated there.

She said that the fear and terror eating them alive was what happened when she hid in a corridor of the hospital. Her voice was barely audible amid loud booms and explosions.

Israel said it had killed 20 militant during Monday’s operation. Among those killed, it said, was a senior Hamas official it identified as Faiq Mabhouh, the head of operations for the internal security forces of the Hamas government in Gaza, who was “armed and hiding in a compound” at the hospital. Hamas did not confirm his death or role in the organization and did not immediately respond to a request for comment.