Israeli troops are attempting to eradicate more senior members of Hamas in the Gaza Strip after it announced the killing of the Islamic group's leader, Yahya Sinwar. They now say they want his brother.

Military officials say they killed dozens more Hamas fighters through Friday during an operation in the northern city of Jabalia.

They announced the killing of Sinwar on Thursday.

Israel Defense Forces Spokesperson Daniel Hagari says they are searching for his younger brother, Muhammad, who is believed to be one of the plotters of the attack on Israel in October last year.

Leaders in Israel are said to believe the killing of Yahya Sinwar could be a turning point in securing the release of about 100 hostages in Gaza.

They have reportedly contacted the United States, Egypt and Qatar. The two Arab states are serving as mediators in negotiations for a ceasefire.

Reports say US President Joe Biden told Israeli Prime Minister Benjamin Netanyahu that he will send Secretary of State Antony Blinken to Israel with a focus on resuming talks.

A senior Hamas official who spoke to NHK on Friday struck a defiant tone, saying they have grown "stronger and more popular" every time the group's leaders have been killed.

He also said, "Hamas is a liberation movement led by people looking for freedom and dignity, and this cannot be eliminated."

Qatar-based broadcaster Al Jazeera says some of the candidates to lead Hamas are even more hardline than Sinwar.