Israel attacked at least Nasser Hospital on Monday in a deadly attack in southern Gaza, analyzing new videos from BBC Verify.

The attack reportedly sparked international condemnation and widespread anger, with at least 20 people reportedly killed, including five journalists.

Gaza initial reports said Israel attacked the hospital twice, and nine minutes later, the first explosion hit another first responder and journalist who arrived at the scene.

But new analysis shows that the hospital was attacked four times in total. BBC verification and expert analysis found that two stairs were hit almost simultaneously in the first wave, and the fact that it was considered a single late attack was actually two separate strikes hit the same position within a fraction of a second.

Israel does not allow international journalists to enter Gaza independently. The BBC verified other strikes identified by analyzing dozens of videos provided by freelancers on the ground and material shot by witnesses circulating online.

In the first incident, Israel strikes At 10:08 local time, hit the external staircase on the east side of the hospital (07:08 GMT), killing Hussam al-Masri, a journalist who contributed to Reuters’ live TV.

The BBC verification has now identified another previously unreported explosion on the northern wing staircase, almost simultaneously being overshadowed by a “double-click” strike on the eastern staircase.

New video shows smoke increasing and destruction on both stairs, while emergency workers say the hospital’s operations were attacked.

Other videos show an injured person being taken to the northern stairs, with the hospital’s director of nursing holding chopped and bleeding clothes, said the nurse was wearing the nurse while she was working in the operations department.

NR Jenzen-Jones, Director of Arms Research Services at Weapons and Ammunition Intelligence, said the videotape “appeared to show internal damage consistent with relatively small ammunition, including an inlet hole that prompts ammunition with relatively flat trajectories.”

About nine minutes later, Israeli troops attacked the facility again, with dozens of first responders and journalists gathering on the eastern stairs.

While the media recorded the explosion at the time, a frame-by-frame analysis of the newly emerging video clearly showed that two separate projectiles fired by Israeli forces were far apart in a bare stairwell, with journalists and emergency workers gathering.

Experts disagree with the types of ammunition used in the third and fourth strikes.

Some ammunition analysts worked with the BBC to verify shared footage with the projectiles as the Rahat missile, a guided ammunition that can be launched from tanks, drones and helicopters. Several Israeli media suggested that ammunition used in hospitals was fired by Israeli tanks stationed nearby.

Experts verified with the BBC said the explosion could not have been caused by a single tank, due to the rapid inheritance of ammunition attacks on the hospital.

“If these Lahats were launched from the ground, at least two tanks were involved because the interval between the two effects was too short,” said Amael Kotlarski, an analyst at Janes Defense Intelligence Company. “No tank loader can be reloaded quickly.”

Meanwhile, Mr. Jenzen-Jones said, “The impact of the two projectiles at almost the same time indicates that two tanks may have been fired at the target at the same time.”

Although he said it was impossible to identify the ammunition used with certainty, the obvious physical characteristics and patterns of the flight “hint on the ‘multi-function’ tank gun projectiles, such as the Israeli M339 model”.

Satellite images reviewed by the BBC showed IDF troops within the launch range of the day of the attack 2.5 kilometers northeast of the Nasser Hospital. Other armored vehicles can also be seen nearby.

The IDF said there was no other comment on the newly identified explosion when the BBC verification approached.

Israel’s narrative of the attack has developed since Monday’s attack. It initially said it had already conducted a strike in the hospital area, saying it had “any harm to those not involved” and would open initial inquiries as soon as possible without justifying the attack.

Prime Minister Benjamin Netanyahu said Israel is responsible, It “deeply regrets the miserable misfortune”.

The IDF said Tuesday that the initial investigation found that the troops had identified Hamas’ camera “used to observe IDF troops’ activities” in the hospital area without providing evidence.

In the allegations of some international legal experts, the IDF has not yet admitted to having conducted more than one strike on the hospital, believing it may have violated international law.

The Fourth Geneva Convention prohibits attacks on civilians who are “relative to specific and direct military superiority, related to the expected concrete and direct military superiority.”

Professor Janina Dill of Oxford University said: “A reasonable attacker must expect dozens of civilian casualties because the hospital is full of protected people.”

Professor Dill added that “only the presence of equipment belonging to the opponent” does not mean that hospitals or medical institutions have lost their protected status under war laws.

According to the United Nations, at least 247 journalists have been killed in Gaza since October 7, 2023, the deadliest conflict recorded by journalists.

The Israeli military launched a campaign in Gaza in the wake of Hamas-led southern Israel on October 7, 2023, in which about 1,200 people were killed and another 251 were taken hostage.

According to Hamas-operated health ministry, nearly 62,900 people were killed in Gaza during the same period.