Abu Obeida, the spokesman for Hamass armed wing, has been killed in an air strike in Gaza City, Israel has said.
Israels Defence Minister Israel Katz congratulated the Israel Defense Forces (IDF) and Israels security agency, Shin Bet, for the "flawless execution" in a post on X.
He gave no detail on the time or location of the operation, but the IDF earlier said its aircraft attacked "a key terrorist" in the al-Rimal neighbourhood on Saturday, prompting reports in Israeli media that Obeida had been the target.
Hamas has not confirmed his death. The Palestinian armed group earlier said dozens of civilians were killed and injured in Israeli strikes on a residential building in the district.
Katz warned on Sunday that many more of Obeidas "criminal partners" would be targeted with "the intensification of the campaign in Gaza" - a reference to a recently approved Israeli plan to seize control of Gaza City.
Separately, the IDF and Shin Bet offered more details about Saturdays strikes that targeted the Hamas spokesman.
They said in a joint statement that the operation had been "made possible due to prior intelligence gathered by [Shin Bet] and the IDFs Intelligence Directorate" that had identified his hiding place.
Five missiles struck the second and third floor of the six-storey apartment building simultaneously from two different directions.
The targeted flat had been used as a dentists surgery. Witnesses reported hundreds of thousands of dollars flying into the air because of the strike, with large sums stolen and later recovered by Hamas members.
Obeida was among the few remaining senior members of Hamass military wing from before its deadly 7 October 2023 attack on southern Israel.
The joint statement said Obeida "served as the public face of the Hamas terrorist organization" and "disseminated Hamas propaganda".
Over the past few years, Obeida - believed to be about 40 years old - delivered a number of long diatribes against Israel on behalf of Hamass military wing, the al-Qassam Brigades.
Always masked in a Palestinian scarf, he became an idol to Hamas supporters throughout the Middle East.
In what may have been his final speech on Friday, Obeida said the fate of remaining Israeli hostages would be the same as that of Hamas fighters, warning Israel against its planned invasion of Gaza City.
On Saturday, Hamas accused the IDF of hitting a residential building in the densely populated al-Rimal neighbourhood of Gaza City.
Local journalists reported that at least seven people had been killed and 20 injured in the strikes, with children among the casualties.
The IDF said that prior to the attack "many steps were taken to reduce the chance of harming civilians, including the use of precision weapons, aerial observations, and additional intelligence information".
BBC News has been unable to independently verify the claims of either the IDF or Hamas.
In early August, Israels security cabinet approved a plan to seize control of Gaza City in a fresh offensive, with the stated aim of bringing the 22-month-long war to an end.
The UN has repeatedly warned that a complete military takeover would risk "catastrophic consequences" for Palestinian civilians and Israeli hostages held in Gaza. The UKs ambassador to Israel has said it would be "a huge mistake".
Israeli Prime Minister Benjamin Netanyahu has vowed to defeat Hamas and defied international criticism of his plans to expand the war.
Israels military operation in Gaza began in response to the Hamas-led 7 October attack, in which about 1,200 people were killed and 251 others were taken hostage. Since then, more than 63,000 Palestinians have been killed, according to the Hamas-run Gaza health ministry.
While the operation to capture Gaza City has yet to begin in earnest, Israeli attacks on the city - where nearly a million people live - have been ongoing.
The Israeli military has said it plans to evacuate Gaza Citys entire population and move it to shelters in the south before troops move in. Most of Gazas population has already been displaced many times during the conflict.
More than 90% of the citys homes are estimated to be damaged or destroyed, and the healthcare, water, sanitation and hygiene systems have collapsed.
Last week, conditions of famine were confirmed in Gaza City and its surrounding areas for the first time.