Israel struck one of the main hospitals in the Gaza Strip on Monday and then hit the facility again as journalists and rescue workers rushed to the scene, killing at least 20 people and wounding scores more, local health workers said.

It was among the deadliest of several Israeli strikes that have hit both hospitals and journalists over the course of the 22-month war sparked by Hamas' October 7, 2023, attack, and the attack came as Israel plans to widen its offensive to heavily populated areas.

Israeli Prime Minister Benjamin Netanyahu's office said the strike on Nasser Hospital in the southern city of Khan Younis was a “tragic mishap” and that the military was investigating.

The first strike hit an upper floor of the hospital housing operating rooms and doctors' residences, killing at least two people, according to Zaher al-Waheidi, head of the records department at the Gaza Health Ministry.

The second strike hit an external stairwell as rescuers and journalists raced to the scene of the first, killing another 18. Around 80 people were wounded, including many in the hospital's courtyard, al-Waheidi said.

Among those killed was 33-year-old Mariam Dagga, a visual journalist who had worked for The Associated Press.

Dagga regularly reported for multiple outlets from the hospital, including a recent story for the AP on doctors struggling to save children from starvation.

The strike killed four other journalists who had worked for Al Jazeera, Reuters and Middle East Eye, a U.K.-based media outlet, most on a contractor or freelance basis.

Reuters said that ahead of the first strike, it was showing live video from the hospital when the feed suddenly shut down.

The journalist filming the live video was killed in the first strike, Reuters said, citing hospital officials.

Video shot from across the street by pan-Arab channel Al Ghad showed people climbing the external stairwell just after the first strike, past walls with chunks shorn off — followed by the boom of the second strike, a huge plume of smoke and a heap of wreckage.

Israeli media reported that Israeli troops fired two artillery shells at the hospital, targeting what they suspected was a Hamas surveillance camera on the roof.

Brig. Gen. Effie Defrin, an Israeli military spokesman, said the army does not target civilians and had launched an internal investigation into the strikes.

He accused Hamas of hiding among civilians but did not say whether Israel believed any militants were present during the strikes on the hospital.

Netanyahu’s statement said Israel “deeply regrets the tragic mishap that occurred today at the Nasser Hospital in Gaza. Israel values the work of journalists, medical staff, and all civilians.”

Israel has attacked hospitals multiple times throughout the war, asserting that Hamas embeds itself in and around the facilities, though Israeli officials rarely provide evidence.

Hamas security personnel have been seen inside such facilities over the course of the war, and parts of those sites have been off limits to reporters and the public.

The hospitals that remain open have been overwhelmed by the dead, wounded and now by increasing numbers of malnourished as parts of Gaza are now in famine.

The war in Gaza has been one of the bloodiest for media workers, with 189 Palestinian journalists killed by Israeli fire, according to the Committee to Protect Journalists. More than 1,500 health workers have been killed, according to the U.N.

Gaza's health ministry said Sunday that at least 62,686 Palestinians have been killed in the war. It does not distinguish between fighters and civilians but says around half have been women and children.

The ministry is part of the Hamas-run government and staffed by medical professionals. The U.N. and independent experts consider it the most reliable source on war casualties. Israel disputes its figures but has not provided its own.

The war began when Hamas-led militants abducted 251 people and killed around 1,200 people, mostly civilians, in the 2023 attack.

Most of the hostages have been released in ceasefires or other deals, but 50 remain in Gaza, with around 20 believed to be alive.