On Thursday, following a siege that lasted several days and included artillery attacks, Israel Defense Forces (IDF) special operations troops raided Gaza's Nasser Hospital. The raid was undertaken in part because of intelligence obtained by Israel that the remains of hostages were in the hospital building.

The Israel Defense Forces (IDF) said it had detained a number of suspects in Thursday’s raid, which it said was led by intelligence gathered in part from released hostages.

Israel said it believed the bodies of dead hostages were being held inside the hospital. Hamas denied the claims, saying the group had “no business” at the hospital.

Israeli forces shelled the hospital early Thursday, killing and injuring an “undetermined number of people,” according to Doctors Without Borders, also known as Médecins Sans Frontières (MSF). Since the attack, one of their colleagues remains unaccounted for.

MSF staff were forced to flee the hospital through a checkpoint set up by the Israeli military, the agency said, adding that one employee “was detained” there.

Hamas has a history of hiding operations and storing weapons in hospitals, schools, and other buildings, including in tunnels beneath the UN's United Nations Agency for Palestinian Refugees (UNRWA) building in Gaza. Last November, the IDF uncovered a massive underground Hamas base under Shifa Hospital in Gaza. 

International agreements generally prohibit attacks on hospitals and medical facilities in times of war, but those facilities can lose that protection if there are known combatants using the facilities as a base of operations.

See Related: IDF Uncovers Secret Hamas Data Center Directly Beneath UNRWA's Gaza HQ

Since the October 7th attacks on Israel by Hamas, Israeli Prime Minister Benjamin Netanyahu has (justifiably) taken a hard line on dealing with Hamas. To date, some, but not all, of Hamas's hostages have been recovered.

See Related: Netanyahu Orders Mossad to Hunt Down Hamas Leaders 'Wherever They Are' 

Israeli Military Rescues Two Hostages From Hamas, Watch Great Joy of Families Welcoming Them Home

A senior Israeli commander, speaking presumably based on intelligence gathered by the IDF, indicated that Hamas terrorists were still in the hospital.

Commenting on Thursday’s raid, Israeli Rear Admiral Daniel Hagari said, “Hamas terrorists are likely hiding behind injured civilians inside Nasser hospital right now.” One former hostage told CNN last month that she was held at Nasser Hospital – a claim CNN could not independently verify, and which Hamas denied.

Israeli military bulldozers dug up the mass graves inside the complex walls, Dr. Al-Qidra, spokesperson for the Ministry of Health, said earlier. On Thursday, the forces “stormed the maternity building and conducted a search operation inside,” he added.

At least one released hostage has confirmed being held by Hamas as a prisoner in Nasser Hospital. Sharon Alony Cunio was released in November, along with her 3-year-old twins, after being held in several locations, including the hospital. Cunio's husband David remains a hostage in Gaza; his whereabouts are unknown as of this writing.

Nasser Hospital is the only remaining functional hospital in the southern Gaza Strip. The hospital was originally built in 1957 during the Egyptian occupation of Gaza. Nasser Hospital opened in 1960 but was closed for two years in the early '70s to increase the number of beds.