Hamas is accusing Israel of sending the Gaza ceasefire process back to "square one", rejecting calls to extend the current temporary truce and demanding negotiations on a lasting peace begin immediately.
There has been a furious response across the Arab world to the announcement by Israeli Prime Minister Benjamin Netanyahu to block all aid deliveries entering Gaza, which is being labelled as a clear breach of international law.
Mr Netanyahu said it was in response to Hamas's rejection of what Israel is describing as a US proposal to continue phase one of the ceasefire through to mid-April, in a bid to secure the release of more Israeli hostages.
Despite the plan being attributed to President Donald Trump's Middle East envoy Steve Witkoff, the White House has largely left it to the Israeli government to articulate the details.
[YOUTUBE: Gaza ceasefire expires]In a video statement, senior Hamas official Osama Hamdan said Israel was breaking from the staged peace negotiations agreed to in January, delaying talks on phase two of the truce.
"The occupation is pushing to return things to square one and overturn the agreement through the alternatives it is proposing, such as extending the first phase or creating an intermediate phase and other proposals that do not conform to what was stated in the agreement signed between the parties," Hamdan said.
"Netanyahu's recent decisions to adopt the American proposals … contradict what was agreed upon, which we consider a blatant attempt to evade the agreement and avoid entering into negotiations for the second phase.
"We condemn the cheap blackmail practised by Netanyahu and his extremist government against our people by using humanitarian aid as a bargaining chip in the negotiations."
On Sunday, the Israeli prime minister said Hamas needed to learn there would be no more "free lunches" as he blocked aid to the strip, while Hamas said the Israeli decision amounted to a "war crime".
The temporary extension proposal demands Hamas immediately release half of the more than 59 Israeli hostages still held in Gaza, more than half of whom are believed to be dead, without providing any guarantees about the course of negotiations for a lasting peace.
Saudi Arabia urges end to aid 'extortion'
Mr Netanyahu and his former defence minister Yoav Gallant are already subject to arrest warrants issued by the International Criminal Court, including on the grounds of using "starvation as a method of warfare".
Arab countries came out in force after the aid blockade was announced, condemning Israel for its decision.
Saudi Arabia — one of the most influential players in the region, courted by the United States to make peace with Israel — called on the international community to put an end to the "grave Israeli violations".
"The use of aid as a tool of extortion and collective punishment constitutes a blatant violation of international law and a direct infringement of the basis of international humanitarian law, especially in light of the humanitarian catastrophe facing the Palestinian people," the country's foreign ministry said.
Egypt, which is acting as a meditator between Israel and Hamas, accused Israel of using starvation as "a weapon against the Palestinian people".
Israel's eastern neighbour Jordan said the decision threatened "to reignite the situation" in Gaza.
Arab leaders to discuss Gaza future
Arab leaders will meet in Cairo on Tuesday to discuss the future of Gaza, and to try to thrash out a plan for rebuilding the strip as an alternative to the idea floated, but not fully explained, by US President Donald Trump.
The Reuters news agency reported the Egyptian government would propose replacing Hamas as the governing power in Gaza.
In its place, a new oversight body would be established to manage aid and reconstruction, controlled by Arab, Muslim and western countries.
Hamas has previously rejected proposal to impose new governance arrangements on the Palestinian people.
Israel has said Hamas and the Palestinian Authority, which exercises some control over the occupied West Bank, could not have any role in governing Gaza.
Negotiations on phase two of the ceasefire would need to deal with the longterm management of the strip, as well as matters regarding the Israeli military's withdrawal from the territory.
