U.S. Secretary of State John Kerry began a diplomatic push on Monday to try to secure a cease-fire between Israel and Hamas but senior U.S. officials acknowledged this would be challenging.
More than 500 people have died in the Gaza Strip fighting, the vast majority of them Palestinians, as Israel has pursued an air and ground offensive to try to stop rocket attacks on its territory from the Hamas-dominated Gaza Strip.
Kerry was to begin his consultations, which are expected to include meetings with top officials in Egypt and possibly elsewhere in the region, with U.N. Secretary-General Ban Ki-moon in Cairo on Monday night, U.S. officials said.
He plans to stay in Cairo until Wednesday morning and has no currently scheduled end to his trip, which may also entail talks with officials from Qatar. The Gulf state has relatively close ties to Hamas and hosts its leader Khaled Meshaal.
Speaking as Kerry flew to Cairo, senior U.S. officials stressed the difficulty of ending the conflict, noting that Egypt's current government has poorer relations with Hamas than its predecessor led by the Muslim Brotherhood's Mohamed Mursi.
"Our goal is to achieve a cessation of hostilities as soon as possible," one senior State Department official said. "We don't expect it will be easy, though. This is a very complicated dynamic."
Among the complexities are the fact that the United States has no direct contact with Hamas, which it regards as a terrorist group, and so must work through proxies, including Egypt and Qatar, which have their own tensions with the group.
Qatar was a strong supporter of Mursi's government, which was ousted by the Egyptian military and its then chief Abdel Fattah al-Sisi, who has since been elected Egypt's president.
"We believe that the effort to reach a cease-fire this time around is going to be in some ways more complicated than it was in 2012," said the U.S. official.
"The region is more divided now than it was then," he added, referring to the "complicated relationships" of those countries believed to have some influence over Hamas. While he did not name these countries, they are widely thought to be Egypt and Qatar.
Mistrust between Egypt and Hamas has also complicated efforts to end the bloodshed in Gaza, where 536 mostly civilian Palestinians, including almost 100 children, have been killed according to Gaza health officials. Israel says 25 of its soldiers have also died, along with two civilians.
Hamas is an offshoot of the Muslim Brotherhood, which was removed from power by the Egyptian army. Hamas rejected Cairo's truce proposal, saying it was not consulted and that the terms were unacceptable.
But there are signs that Egypt, which has long regarded itself as the most effective mediator in the Arab-Israeli conflict, may show some flexibility and amend the initiative, three Egyptian officials told Reuters.
"Egypt does not mind adding some of Hamas' conditions provided that all involved parties approve," one senior Egyptian official said, without giving details.
Among Hamas' conditions are the lifting of the Israeli and Egyptian blockade on Gaza and the release of several hundred Palestinians arrested by Israel last month during its search for three Jewish teenagers abducted in the West Bank. The trio were later found dead in a killing Israel blamed on Hamas.
But Egyptian Foreign Minister Sameh Shukri said Cairo has no plans to revise its ceasefire proposal, saying it guarantees the opening of border crossings between Egypt and Israel.
"The initiative clearly states that border crossings get opened after a ceasefire and when security stabilises," Shukri said at a news conference with U.N. chief Ban in Cairo.
Ban is expected to meet senior Egyptian officials on the Gaza crisis as part of a Middle East tour.
"If you really want to discuss all these conditions it will take a long time... I'm urging that unconditionally that violence must be stopped by both sides," said Ban.
Egyptian officials suspect Hamas rejected the ceasefire plan at the urging of Qatar, a strategic player in reaching an effective deal as host to a large number of exiled Islamists from across the Middle East, including Hamas leader Khaled Meshaal.
Additional reporting by Shadia Nasralla; Editing by Michael Georgy and Tom Heneghan