LONDON — A senior Hamas official was killed in an Israeli airstrike on a hospital in southern Gaza on Sunday, the terror group and the Israel Defense Forces said, as Israel expanded its renewed campaign into the Palestinian territory.

Ismail Barhoum, a senior member of Hamas’ political bureau, was killed in the strike on the Nasser Hospital in Khan Younis, Hamas confirmed, describing the attack as a “cowardly” assassination. Hamas said Barhoum was receiving medical treatment in the hospital when he was killed.

The IDF and Israeli Security Agency said in a joint statement that the attack targeted a “key terrorist in the Hamas terrorist organization” who was “operating inside” the hospital, which is the largest in southern Gaza.

The Hamas-run Gaza Health Ministry said the Israeli strike targeted the hospital’s surgical wing and occurred when “many patients and wounded” were inside the hospital. Videos from the scene showed a fire inside the building following the strike.

The ministry said that “many others” — including medical personnel — were wounded in the strike, “with varying degrees of injuries.” The attack, it added, “also caused panic and forced the complete evacuation of the department after a large portion of it was destroyed.”

Nasser Hospital has been shelled several times by Israeli forces since war broke out in Gaza on Oct. 7, 2023, following Hamas’ surprise attack into southern Israel.

IDF forces raided the hospital in February 2024, when the IDF said it had intelligence that hostages taken during the Oct. 7 attack had been held there. Israel has repeatedly alleged that Hamas was using the facility as a “command-and-control center.” Hamas has denied using Nasser and other Gaza hospitals for military purposes.

Israel resumed its air and ground campaign in Gaza last week, ending the ceasefire agreed with Hamas in January.

At least 673 people have since been killed and 1,233 injured by Israeli strikes since the ceasefire ended, according to the Gaza Health Ministry. The total death toll in Gaza since Oct. 7, 2023, is now at 50,021, according to the ministry.

ABC News’ Diaa Ostaz, Will Gretsky and Victoria Beaule contributed to this report.