US Secretary of State Hillary Clinton is seeking a truce between Israel and Hamas as diplomatic efforts are taking place in Cairo, Ramallah and Jerusalem, amid continued violence in Gaza.
Clinton arrived in Cairo for talks with President Mohamed Morsi on Wednesday after holding talks with Israeli and Palestinian officials in the occupied West Bank and Israel.
At least 149 Palestinians and five Israelis have been killed since the violence began eight days ago.
Late on Tuesday a Hamas official said an anticipated announcement of a Gaza truce agreement with Israel had been delayed until Wednesday.
Israel Radio quoted an Israeli official saying a truce was held up due to "a last-minute delay in the understandings between Hamas and Israel."
Clinton spoke of a deal "in the days ahead".
Al Jazeera's Tom Ackerman, reporting from Jerusalem, said: "What they are looking for is a general statement coming from the Egyptian government to say there will be a 48-hour test period and then a long-term solution, rather than direct talks between Israel and Hamas."
A UN Security Council statement condemning the conflict was blocked on Tuesday by the US, which complained that it "failed to address the root cause," the Palestinian rockets.
Israeli Prime Minister Binyamin Netanyahu, who faces an election in two months that he is, for now, favoured to win, told Clinton he wanted a "long-term" solution.
Failing that, Netanyahu made clear, he stood ready to step up the military campaign to silence Hamas' rockets.
Clinton assured Netanyahu of "rock-solid" US support for Israel's security, speaking of seeking a "durable outcome" and of Egypt's "responsibility" for promoting peace.
More violence overnight in Gaza
"In the days ahead, the United States will work with our partners here in Israel and across the region toward an outcome that bolsters security for the people of Israel, improves conditions for the people of Gaza and moves toward a comprehensive peace for all people of the region," Clinton said on Tuesday.
Netanyahu, who has appeared in no immediate rush to repeat the invasion of winter 2008-09 in which more than 1,400 Palestinians were killed, said: "If there is a possibility of achieving a long-term solution to this problem with diplomatic means, we prefer that.
"Loss of human life"
Also on Tuesday, the UN Secretary-General Ban Ki-moon held talks with Netanyahu in Jerusalem.
"Regrettably, I'm back again in the region only nine months since my last visit, because of violence in Israel and Gaza...the world is extremely concerned at the rising loss of human lives," Ban said.
He was also to meet Abbas to discuss the crisis.
A delegation of nine Arab ministers, led by Mohamed Amr, Egypt's foreign minister, visited Gaza in a further signal of heightened Arab solidarity with the Palestinians.
Arab league chief Nabil El-Araby said a ceasefire is not the the real issue facing Gaza.
"The real problem is not a truce. The real problem that the Arab and Islamic countries and all friendly countries in the world must focus on is ending the occupation," said el-Araby.
|Follow the latest developments in the ongoing conflict
More than a dozen Palestinians were killed in attacks on Gaza on Wednesday, according to medical sources.
Palestinian emergency services said that two brothers in the southern town of Rafah were killed in a strike that hit their motorcycle on Tuesday night. Four others were killed in raids around the central town of Deir al-Balah, they added.
Israel also confirmed a strike on a building housing the offices of media organisations, the third such strike in three days. It said that it carried out a "surgical" strike on "a Hamas intelligence operations centre" in these building.
Al Jazeera's bureau in Gaza was also damaged as a missile hit a building nearby, no casualties were reported.
"I was in the office with a fixer and suddenly we heard an explosion," said Mahmud Hams, an AFP photographer, adding that the explosion shook the building. "About five minutes passed and then we heard two more loud explosions that also shook the building," he said.
A soldier was killed by a mortar in the Eshkol border region, according to the Israeli military. Later, a civilian was killed when a rocket landed in the same region.
The Israeli military has struck at least 1,450 targets in Gaza since attacks began last Wednesday.
Since then, at least 760 rockets have hit Israel while almost 400 others have been intercepted by Israel's anti-missile system, the Iron Dome, according to the Israeli arm.