Israel's military says it was targeting a Hamas commander in a strike on the Jabalia refugee camp in Gaza in which dozens of people are said to have died.IDF spokesperson Daniel Hagari said the strike killed Ibrahim Biari, who it says was one of the leaders of the massacres in Israel on 7 October.
He was also the "main leader" of Hamas's combat operations since Israeli forces entered Gaza, Rear Admiral Hagari said in a news conference.
The strike is said to have killed several other militants and collapsed the group's infrastructure "in the building and underground".
"The purpose of that infrastructure was to carry out terrorist activities against our forces," he added.
Gaza’s Hamas-run health ministry said at least 50 people were killed and 150 wounded by the Israeli air strike.
Ayed al Bazm, a spokesman for Gaza's Hamas-run interior ministry, said six bombs hit the area, with apartment blocks in residential areas damaged in the explosions.
Images from the scene showed people searching for survivors inside wrecked buildings, and people climbing through several large craters.
Mr Hagari repeated Israel's accusations that Hamas uses Palestinian civilians as "human shields" and said people should move south. Israel has declared northern Gaza an evacuation zone.
It comes as Israel said its forces fought Hamas gunmen inside the militants' vast tunnel network beneath Gaza.
The tunnels under the cramped enclave are a prime objective for Israel as it expands a four-day-old ground offensive - after three weeks of aerial bombardment - into Gaza from the north to hit Hamas in retaliation for the Islamist group's deadly surprise attack into southern Israel on October 7.
Some of the 240 hostages that Israel says were seized by Hamas that day are believed to be held in the tunnel complex, adding a further complication for the Israelis on top of the difficulties of fighting in an urban setting.
"Over the last day, combined IDF (Israel Defence Forces) struck approximately 300 targets, including anti-tank missile and rocket launch posts below shafts, as well as military compounds inside underground tunnels belonging to the Hamas terrorist organization," an Israeli military statement said.
Militants responded with anti-tank missiles and machine gun fire, it said. A number of militants were killed, it said, without specifying a number.
Hamas said in a statement its fighters were engaging in fierce battles with Israeli ground forces, who were taking losses. "The occupation is pushing its soldiers into proud Gaza, which will always be the cemetery of invaders," Hamas said.
Israeli forces also bombed the narrow coastal enclave overnight in air, sea and ground attacks, hitting northwestern areas, witnesses said on Tuesday.
On Monday, Israeli forces targeted Gaza's main north-south road and attacked Gaza City, its northern hub, from two directions.
Gaza health authorities say that 8,525 people, including 3,542 children, have been killed in Israeli attacks since Oct. 7. U.N. officials say more than 1.4 million of Gaza's civilian population of about 2.3 million have been made homeless.
About 1,400 people, mainly civilians, were killed in the cross-border Hamas assault on Oct. 7, Israel says.
Reuters has been unable to independently verify casualty counts.