Hundreds of thousands of Israelis rallied across the country on Sunday, demanding Prime Minister Benjamin Netanyahu to negotiate a ceasefire with Hamas and secure the return of hostages held in Gaza.

Around 700,000 people participated in demonstrations on main roads and at junctions nationwide, with 550,000 attending the central rally in Tel Aviv, according to Israel's Ynetnews. The protests began in the morning after the Israel Defense Forces (IDF) announced the recovery of six hostages' bodies and continued through the night.

Protesters waved Israeli flags and chanted "A deal – Now!" Many carried posters featuring the hostages. There are still 101 hostages in Gaza, with about half presumed dead due to either Hamas attacks or Israeli bombings.

Einav Zangauker, the mother of a hostage named Matan Zangauker, addressed the crowd, claiming that there was "a deal proposal on the table," but Netanyahu refused to accept it to avoid losing support from his coalition of pro-settler leaders.

The demonstrations are expected to continue into Monday with a general strike. Arnon Bar-David, secretary-general of the Histadrut, Israel's largest workers' organization, announced the strike on live television, accusing Netanyahu of hindering the deal due to "political considerations."

In reaction to the killing of six hostages, including an Israeli American citizen, several U.S. Democratic lawmakers renewed calls for an Israeli-Hamas ceasefire on Sunday.

U.S. National Security Advisor Jake Sullivan held a virtual meeting on Sunday with the families of the American hostages held by Hamas in Gaza, discussing the ongoing diplomatic push to drive towards a deal that secures the release of the remaining hostages.

"A ceasefire must be reached immediately that allows all remaining hostages to be released, humanitarian aid to flow into Gaza, and an elusive and neglected long-term vision for peace and stability to become a reality," said Democratic U.S. Senator Dick Durbin.

Meanwhile, Israeli military operations continued in the West Bank, killing or injuring dozens of Palestinians over the past few days.

Egypt condemned the ongoing Israeli efforts to escalate confrontations within the Palestinian territories, including the West Bank and East Jerusalem, as well as Israel's continued use of "excessive military force and unlawful killings."

Qatar's Foreign Ministry described in a statement the Israeli operation in West Bank as "heinous and horrific crimes" and a "flagrant violation of international legitimacy resolutions."

Separately, the first phase of polio vaccination began in central Gaza on Sunday. The second phase is scheduled for September 5 in Khan Younis in southern Gaza, with northern Gaza set to be covered on September 9.

Philippe Lazzarini, commissioner-general of the United Nations Relief and Works Agency for Palestine Refugees in the Near East, urged for a permanent ceasefire to ensure success of the polio vaccination campaign.

A statement from Netanyahu's office on Saturday dismissed reports of a general ceasefire for vaccination, confirming only a humanitarian corridor and designated safe areas for vaccine administration.

(With input from agencies)