Hamas wants written guarantees from the United States for a permanent ceasefire and the withdrawal of Israeli forces from the Gaza Strip in order to sign off on a US-backed truce proposal, two Egyptian security sources said.

Mediators Qatar and Egypt said Hamas had responded on Tuesday to the phased ceasefire plan for an end to the eight-month Israeli war on Gaza, without giving details, Middle East Eye reported. 

The Egyptian sources and a third source with knowledge of the talks said Hamas had concerns that the current proposal does not provide explicit guarantees over the transition from the first phase of the plan, which includes a six-week truce and the release of some captives, to the second phase, which includes a permanent ceasefire and Israeli withdrawal.

The Egyptian sources said Hamas would only accept the plan if the guarantees were in place, and Egypt was in contact with the US about the demand.

"Hamas wants reassurances of an automatic transition from one phase to another as per the agreement laid out by US President Biden," the third source said.

Hamas and Egyptian authorities did not immediately respond to requests for comment.