Hamas's military wing said Sunday that the commander of its northern brigade, Ahmed Al-Ghandour, and three other senior leaders had been killed during Israel's offensive against the Islamist movement.
In a statement, the Ezzedine Al-Qassam Brigades said Ghandour was a member of its military council and named three other leaders who had died, including Ayman Siyyam, who Israeli media said was head of the Hamas rocket-firing units.
It said Ghandour was a top Hamas commander who headed its northern Gaza brigade and was part of its military council.
"We pledge to Allah we will continue their path and that their blood will be a light for the mujahedeen and a fire for the occupiers," the statement said, without saying when they were killed.
Last week, a senior Israeli military official said troops had killed "more than 50" Hamas commanders causing "significant" harm to the capacity of the military wing, which the official estimated to have around 24,000 fighters.
Ghandour spent two stints behind bars in Israel and reportedly lost two of his sons in Israeli airstrikes during the current war.
During the 2014 war, troops reportedly destroyed his house over his role in firing rockets at Israel and a year later, an Israeli NGO named him in a lawsuit for alleged war crimes during that conflict.
Ghandour -- whose nom de guerre was Abu Anas -- was put on a US economic sanctions blacklist in 2017 as a "global terrorist".
The State Department said at the time he was a member of Hamas's political bureau, as well as having previously been on the fighter group's Shura council, which groups its leaders from Gaza, the West Bank and overseas.
It said he had been involved in "many terrorist operations" including a 2006 attack on an Israeli military post at the Kerem Shalom border crossing which killed two soldiers and wounded four others.
That attack resulted in the kidnapping of Israeli soldier Gilad Shalit, who was held by Hamas for five years before he was freed in 2011 in exchange for 1,027 Palestinian prisoners.
- 'Significant harm' -
The Gaza war began on October 7 when Hamas fighters stormed into southern Israel, killing 1,200 people, mostly civilians, and snatching some 240 others, according to an Israeli count.
Israel has struck back with a huge military campaign that Gaza's Hamas rulers say has killed nearly 15,000 people, also mostly civilians.
The senior Israeli military official said troops had caused significant damage to Hamas's fighting force -- made up of 24 battalions of 1,000 militants each -- notably in the north.
"In some (battalions), we eliminated hundreds of Hamas terrorists and most of the battalion commanders," he said.
"This harm is significant, it dismantles the ability of Hamas to fight right now, but also the ability to rehabilitate its military power after the war."
He did not give a number of fighters killed but said it was in the several thousands: "not 10,000, not 1,000, something in the middle".
The Hamas announcement Sunday came on the third day of a four-day pause in the fighting during which Hamas has handed back 26 Israeli hostages, all women and children, in two batches as well as 15 foreign nationals, mostly Thais.
In return for the Israeli hostages, Israel has freed 78 Palestinian prisoners, all of them women and teenagers.