Israel threatened to resume "intense fighting" in Gaza if hostages were not released this weekend, while Hamas insisted it remained committed to the ceasefire deal and accused Israel of violations.
Under the terms of the ceasefire, which has largely halted more than 15 months of fighting in Gaza, captives were to be released in batches in exchange for Palestinians in Israeli custody. So far, Israel and Hamas have completed five hostage-prisoner swaps.
But the deal has come under increasing strain in recent days, prompting diplomatic efforts to salvage it and Hamas to say it was "committed to the ceasefire".
Israeli Prime Minister Benjamin Netanyahu said that "if Hamas does not return our hostages by Saturday noon, the ceasefire will end, and the IDF (Israeli military) will resume intense fighting until Hamas is decisively defeated".
His threat echoed that of US President Donald Trump who said on Monday that "hell" would break out if Hamas failed to release "all" Israeli hostages by Saturday.
Tensions, which initially spiked after Trump proposed last month taking over Gaza and removing its more than two million inhabitants, have grown following his latest comments.
"As far as I'm concerned, if all of the hostages aren't returned by Saturday 12 o'clock... I would say cancel it and all bets are off and let hell break out," Trump said.
While hosting Jordan's King Abdullah II at the White House on Tuesday, Trump was asked whether his deadline still held, and said "Yes".
Senior Hamas leader Sami Abu Zuhri said Trump's remark "further complicates matters".
"Trump must remember that there is an agreement that must be respected by both parties," he told AFP.
Late on Tuesday, the group again insisted it was "committed to the ceasefire agreement" but said Israel "is the party that did not abide by its commitments and is responsible for any complications or delays".
King Abdullah, asked at the White House about Trump's widely criticised proposal to displace Gazans, said only that Egypt was coming up with a response.
Posting later on X, the king said he "reiterated Jordan's steadfast position against the displacement of Palestinians", adding that it was "the unified Arab position".
PLANNED RELEASE
Hamas has said it would postpone the next hostage release, scheduled for Saturday, accusing Israel of violating the deal and calling for it to fulfil its obligations.
UN chief Antonio Guterres has urged Hamas to proceed with the planned release and "avoid at all costs resumption of hostilities in Gaza".
Yemen's Huthi rebels, who are aligned with Hamas and have launched attacks throughout the war in support of the Palestinians, said they were "ready to launch a military intervention at any time in case of escalation against Gaza".
Netanyahu did not specify whether he was referring to all captives, but his Finance Minister Bezalel Smotrich called on the premier to "open the gates of hell" if Israel doesn't get back "all the hostages... by Saturday".
"No more phases, no more games," far-right leader Smotrich said, calling to stop all humanitarian aid and demanding the "full occupation of the Gaza Strip".
The Israeli military said it had decided "to raise the level of readiness" of its forces near the Gaza Strip and "increase reinforcements with additional troops, including reservists".
Outside Netanyahu's office in Jerusalem, families of hostages rallied with pictures of their loved ones, calling for the implementation of the agreement.
"There is a deal. Go for it!" said Zahiro, whose uncle, Avraham Munder, died in captivity in Gaza.
In Gaza, concerns over the fate of the ceasefire were prevalent.
"I pray that the ceasefire holds, but... the ruling faction in Israel wants war, and I believe there is also a faction within Hamas that wants war," said Adnan Qassem, 60, from Deir el-Balah.
