Quartet Representative Tony Blair is due to join officials in Cairo for ceasefire talks.
A delegation from Palestinian groups, including militant organizations Hamas and Islamic Jihad, met in Cairo on Sunday for indirect ceasefire talks with Israel to be conducted through Egyptian officials, Egyptian and Palestinian sources said.
Truce talks would include Hamas' demand that Egypt ease movement across its border with blockaded Gaza. Israel said on Saturday it would not send envoys as scheduled, accusing enemy Palestinian Islamists of misleading international mediators.
A US/UN-brokered ceasefire proposal broke down within two hours on Friday, with Israel and Hamas trading blame. The talks on Sunday started with Palestinian factions finding common ground before starting negotiations with Egypt, the sources said.
Qais Abu Laila, a senior leader from the Democratic Front for the Liberation of Palestine who was in Cairo, said the different Palestinian factions had agreed on a unified list of conditions.
"Ceasefire, the pullout of Israeli forces, ending the blockade, releasing the prisoners ... and starting the reconstruction process," he told Reuters by phone.
"There are details attached to each of these points and there will be a meeting soon with the Egyptian side to discuss the (Palestinian) paper," he said.
US Deputy Secretary of State Bill Burns and former British prime minister Tony Blair are expected to fly to Cairo for the negotiations, airport sources said.
Egypt, which shares a border with Gaza and like Israel opposes Hamas, has positioned itself as a mediator for the Gaza conflict.
Israel began its air and naval offensive against Gaza on July 8 following what it said was a surge of cross-border rocket salvoes by Hamas and other guerrillas. Israel later also launched ground incursions.
Palestinian officials say over 1,800 people, most of them civilians, have been killed in Gaza. Israel has confirmed that 64 soldiers have died in combat, while Palestinian shelling has also killed three civilians in Israel.