Israel-Gaza updates: Police killed in border shooting, authorities say

Hamas has issued a new threat tying Prime Minister Benjamin Netanyahu's premiership to the fate of the surviving Gaza hostages.

"Aggression stops = prisoners return alive," a Wednesday morning post on the group's official Telegram channel said. "Aggression continues = prisoners' fate unknown."

"Every day that Netanyahu continues to rule may mean a new coffin," the post -- which was written in English, Arabic and Hebrew -- continued. "The decision is yours."

Hamas and Netanyahu have blamed each other for the failure to reach a cease-fire deal. Hamas said Netanyahu's demands are "aimed at obstructing reaching an agreement to preserve his power."

Netanyahu, for his part, said this weekend of the militant group: "Whoever murders hostages -- does not want a deal."

There are 101 hostages still inside Gaza, around half of whom are believed to still be alive.

-ABC News' Nasser Atta and David Brennan

More than 187,000 children in central Gaza have received polio vaccines since Sunday, according to the World Health Organization (WHO).

WHO Director-General Tedros Adhanom Ghebreyesus wrote on X on Wednesday that the "first phase of polio vaccination in central Gaza is complete," with more than 187,000 children under the age of 10 vaccinated.

That is higher than the target number of 156,500, Ghebreyesus said.

"Four fixed sites will continue to offer polio vaccination for the next three days in central Gaza to ensure no child is missed," the WHO chief added.

Preparations are underway to expand the vaccine roll out campaign into southern Gaza, Ghebreyesus said. Vaccinations there are expected to begin on Thursday.

Palestinian health authorities and United Nations agencies hope to vaccinate 640,000 children.

Israel agreed to partial pauses in the fighting in Gaza to facilitate the polio vaccination campaign, saying the drive will continue through Sept. 9 and last eight hours a day.

"We ask for the humanitarian pauses to continue to be respected," Ghebreyesus wrote. "We continue to call for a cease-fire."

-ABC News' Kevin Shalvey and David Brennan

The Hostages and Missing Families Forum will again lead cease-fire and hostage release demonstrations across Israel on Wednesday, according to a schedule posted to social media.

"The public is called to join and come together with the families of the abductees to the houses of the ministers and coalition members and hold demonstrations and protest vigils demanding that they exercise their authority to bring about a deal now," the Forum wrote on X.

Among the gatherings will be one outside the Jerusalem home of Strategic Affairs Minister Ron Dermer -- a former member of the dissolved war cabinet and long considered a close ally of Prime Minister Benjamin Netanyahu.

Activists plan to protest at the homes of eight other government ministers and three members of parliament, the Forum said.

-ABC News' Jordana Miller and David Brennan

Far-right National Security Minister Itamar Ben-Gvir said he is "working to stop the negotiations with Hamas," as talks over a cease-fire and hostage release deal continue under massive public and international pressure.

Ben-Gvir -- one of the most vocally hawkish members of Prime Minister Benjamin Netanyahu's government -- wrote on X that Israel should end negotiations and cut fuel and electricity to Gaza in response to Hamas' recent killing of six hostages in the southern strip.

"Continuing the negotiations only spurs them to produce more and more terror," including in the West Bank, Ben-Gvir said.

Ben-Gvir is a longstanding proponent of expanding Israeli settlements in the West Bank. He has called on the government to "encourage" Israelis to settle in Gaza while suggesting "voluntary emigration" of Palestinians from the territory.

Ben-Gvir was convicted of incitement to racism and supporting a terror organization in 2008, related to an anti-Arab placard he displayed at a protest following a Palestinian terrorist attack in Jerusalem. Signs referring to the far-right Kach movement -- a Jewish group banned as a terror organization -- were also found in his car.

-ABC News' Guy Davies and David Brennan