The PLO has said that all Palestinian factions, including Hamas and Islamic Jihad, have united to offer a 24-hour ceasefire in Gaza, a move Hamas however insisted must be guaranteed by Israel for it to work.
Yasser Abed Rabbo, a member of the PLO executive committee, said on Tuesday that a 24-hour truce offer was agreed and that a unified delegation could be sent to Cairo to talk about the next steps.
The UN and diplomats have over the past week tried to broker a temporary halt to violence in Gaza, in order to create conditions for talks in Cairo between all parties for a full ceasefire.
"The factions, including Hamas and Jihad, are prepared for a 24-hour truce and Israel will be held responsible if it doesn't accept the truce as well," he said.
"There is a proposal from the UN to extend the truce to 72 hours. And we look favourably upon that. This is more proof that we have a unified Palestinian stand. "
However Osama Hamdan, a Hamas spokesman in Beirut, Lebanon, said that the organisation welcomed the idea of a ceasefire "but we need a guarantee that the Israelis will not violate that".
Israel's government spokesman Mark Regev told the AP news agency that the offer was "not serious" until Israel heard from Hamas directly.
An Israeli security cabinet meeting scheduled for 4pm GMT on Tuesday, which could have proven crucial to the offer, has been postponed.
Later on Tuesday, Mohammed Deif, the head of Hamas' military wing the Qasam Brigades, restated the group's position on the terms of a full ceasefire.
"The ceasefire will not take place unless the siege is lifted and the border crossings are all open ... the Zionist entity will not know security unless the Palestinians people live in peace," he said.
Israel continues to pound the Gaza Strip. At least 100 Palestinians were killed on Tuesday, according to Gaza officials. The total Palestinian death toll in more than three weeks of Israel-Hamas fighting has exceeded 1,165.
On the Israeli side, 56 people have been killed, most of them soldiers.