WASHINGTON - Hamas has sent back an “unworkable” counter-offer to a US-backed ceasefire proposal for Gaza, Antony Blinken warned on Wednesday.

An official with knowledge of the talks told the Washington Post that Hamas’s amendments had included a “timeline for a permanent ceasefire and the complete withdrawal of Israeli troops from the Gaza Strip.”

Full details of the peace deal and the amendments demanded by Hamas have not been made public. The US says Israel has accepted the deal, but Israel has not publicly backed it.

Two Egyptian security sources told Reuters that Hamas wanted written guarantees from the US for a permanent ceasefire and Israeli withdrawal and had concerns that the current proposal did not provide explicit guarantees over the transition of the first to the second phase.

The spiralling death toll in Gaza and growing public anger in Israel over the government’s handling of the war are adding to pressure on both sides to reach a deal.

On Wednesday, a United Nations commission investigating the Oct 7 attacks on Israel and the ensuing conflict in Gaza accused both Palestinian armed groups and Israel of committing war crimes.

A panel led by Navi Pillay, the former UN human rights chief, found that Israel’s conduct during the war included crimes against humanity.

The report does not carry any penalties but provides a legal analysis that could feed into future action by the International Court of Justice.