US Secretary of State Antony Blinken has arrived in Israel for crunch talks on a Gaza ceasefire deal.
He touched down as negotiations in Qatar between Hamas and Israel were at their most delicate stage.
It is his ninth trip since the war started in October and the hope is that he can help secure a hostage exchange and ceasefire.
However, his visit comes amid further Israeli bombing with claims more than 20 people, including women and children, were killed in a strike on Sunday,
US president Joe Biden has indicated that a deal was closer than it has been but Hamas says suggestions of progress are an "illusion".
The sticking points are said to include whether Israeli troops will be required to withdraw fully from the Gaza Strip, as Hamas insists.
A Hamas source has told Saudi media that the proposals include the IDF maintaining a reduced presence along the Philadelphi Corridor, a narrow strip of land along Gaza’s southern border with Egypt.
But Israeli sources have told the Times of Israel, that other procedures along the border could compensate for an Israeli withdrawal from the area in the first phase of the deal.
The Israeli military launched a campaign in Gaza to destroy Hamas in response to an unprecedented attack on southern Israel on 7 October, during which about 1,200 people were killed and 251 taken hostage.
More than 40,000 people have been killed in Gaza since then, according to the territory's Hamas-run health ministry.
A ceasefire deal agreed in November saw Hamas release 105 of the hostages in return for a week-long ceasefire and the freeing of some 240 Palestinian prisoners in Israeli jails. Israel says 111 hostages are still being held, 39 of whom are presumed dead.
US President Joe Biden said earlier this week "we are closer than we have ever been" to a deal.
But Israeli Prime Minister Benjamin Netanyahu told a cabinet meeting on Sunday that Israel's security was paramount.
He said: "There are things we can be flexible about, and there are things we cannot be flexible about, and we insist on them. We know very well how to differentiate between the two.”
He also accused Hamas of being "obstinate" in negotiations and called for further pressure to be applied on the group.
Meanwhile Hamas put out an official statement rejecting the latest hostage proposal discussed in Doha over the weekend, and blaming Prime Minister Benjamin Netanyahu for putting up new obstacles in the talks.
The group claimed that Netanyahu “sets new conditions and demands” to scupper talks and prolong the war in Gaza.
The statement says that the latest US-backed proposal is aligned with Israel’s demands, pointing at the insistence that the IDF remain in the Philadelphi Corridor, the Rafah Crossing, and the Netzarim Corridor.
The group also blames Netanyahu for introducing fresh conditions around the release of security prisoners.
“We hold Netanyahu fully responsible for thwarting the mediators’ efforts and obstructing an agreement,” Hamas said adding that the prime minister is responsible for the lives of the hostages held in Gaza.
