US Secretary of State reportedly sees 'signs of progress' in brokering truce between Israel, Hamas; on the ground, little has changed.

US Secretary of State John Kerry is not ruling out any options on the shape of a Gaza ceasefire, he said on Wednesday as he intensified efforts to end the bloodshed.

On his third day of shuttling between regional leaders, Kerry said he saw signs of progress on ending two weeks of fighting that has killed more than 700, mostly Palestinians.

He hinted that his discussions hinged on tinkering with an Egyptian ceasefire proposal, which was earlier rejected by Hamas.

"All of the issues of Gaza would be on the table," Kerry told reporters after meeting in Ramallah with Palestinian Authority president Mahmoud Abbas, who comes from the rival Fatah faction, which recently signed a unity pact with Hamas.

Kerry later headed back to Tel Aviv where he entered an evening of talks with Israeli Prime Minister Binyamin Netanyahu, who ordered a ground-and-air campaign that has battered the Gaza Strip in response to Hamas rocket attacks.

The top US diplomat declined to elaborate on potential changes to the Egyptian truce plan, under which Hamas would end its rocket fire into Israel and the Jewish state would stop its military campaign ahead of broader discussions.

The truce was accepted by Israel but rejected by Hamas, the de facto power in Gaza, which has laid down a series of conditions, including the removal of Israel's eight-year blockade on the enclave, leveled to stop weapons and explosives being smuggled in. Hamas also demanded the release of terrorists jailed in Israel, and the establishment of an airport in Gaza, among some of its more outlandish conditions.

Israel has since said it would not end its campaign, dubbed Operation Protective Edge, until it eliminates the tunnels through which Hamas terrorists can infiltrate Israel. Several attempts have been thwarted in the past week, as squads of Hamas and Islamic Jihad terrorists were intercepted by IDF forces on the way to attacking villages and kibbutzim near Gaza in southern Israel.

Since the ground offensive began last week, the IDF have located and destroyed dozens of similar tunnels.

In Washington, deputy national security adviser Tony Blinken called for an agreement that would ultimately result in the demilitarization of the Gaza Strip to prevent further crises.

Beyond a ceasefire

"One of the results, one would hope, of a ceasefire would be some form of demilitarisation, so that again, this doesn't continue," Blinken told National Public Radio.

Kerry has said that the Egyptian plan should serve as the "framework" for a ceasefire but said that the most critical priority was to find a quick end to the violence, which has killed 685 Gazans, according to Hamas sources, as well as 34 Israelis and a foreign worker.

"After the ceasefire, there will be serious negotiations to find a sustainable solution for the situation in Gaza," a US official travelling with Kerry said on condition of anonymity.

Kerry also met UN Secretary General Ban Ki-moon and spoke by telephone Wednesday with the foreign ministers of Qatar and Turkey - whose Islamist governments are staunch allies of Hamas - as well as the top diplomats of Egypt and France.

Kerry said he would return late Wednesday to Egypt. The country is a long-time regional broker, but the military-backed government has strained ties with Hamas.

Kerry flew into Tel Aviv despite a ban by the US Federal Aviation Administration on commercial carriers heading to Israel after a rocket struck a house in the central Israeli city of Yehud, near Ben Gurion airport.

The top US diplomat's custom Boeing 757 - with "United States of America" emblazoned across the livery - arrived without incident at the airport, to which major US and European airlines have suspended services.

A US official said that the US aviation order did not apply to military aircraft, which include Kerry's plane.

Netanyahu has protested against the US move amid fears a prolonged ban could pose risks for Israel's economy, which has generally weathered the conflict.

Kerry said the aviation order - which was renewed on Wednesday - was made solely on safety considerations.