Israel-Gaza crisis: Push for ceasefire amid fresh attacks
International efforts to finalise a ceasefire are being stepped up after a night of renewed Israeli air strikes in Gaza and sporadic Hamas rocket attacks.
US Secretary of State Hillary Clinton is visiting the West Bank and, later, Cairo after talks with Israeli leaders.
Palestinian sources had suggested a truce would be announced on Tuesday, but Israel said no deal was struck.
Some 136 Palestinians and five Israelis have been killed since the flare-up began eight days ago, officials say.
On Tuesday alone, the conflict claimed the lives of at least 20 Palestinians and two Israelis.
Mrs Clinton has arrived in Ramallah on the West Bank for talks with Palestinian Authority President Mahmoud Abbas. UN Secretary General Ban Ki-moon is also visiting leaders in the region to try to cement a ceasefire.
In Cairo, officials from Hamas, the militant Palestinian group that has governed Gaza since 2007, had suggested a truce would come into effect at midnight on Tuesday, but Israel later said it had not agreed to a text.
Israel's demands include no hostile fire of any kind from Gaza and international efforts to prevent Hamas from re-arming, while Hamas is demanding an end to the blockade on Gaza and targeted killings by Israel.
An Israeli official told Israel Radio the ceasefire had not been agreed because of "a last-minute delay in the understandings between Hamas and Israel".
In the early hours of Wednesday, BBC correspondents in Gaza reported hearing loud explosions that were followed by a widespread power cut.
Israeli missiles struck the main complex of the Hamas-run government in the centre of Gaza City.
The BBC's Paul Danahar in Gaza said the huge compound had been laid to waste and was little more than dust and rubble.
The Israeli military later tweeted it had "surgically targeted a Hamas intelligence operations centre" on the seventh floor of a media building.
Israel's military, the Israel Defense Forces (IDF), said it had attacked more than 100 "terror sites" in Gaza overnight "of which approximately 50 were underground rocket launchers".
The health ministry in Gaza said 15 more people had been injured overnight.
The BBC's Jon Donnison in Gaza says the streets were again empty on Wednesday morning, as people tried to protect themselves at home while waiting for something positive to come from talks in Cairo.
Israel says more than 800 rockets have been fired from Gaza into Israel over the past week, 162 in the past day alone.
Many of the rockets have been intercepted by Israel's Iron Dome missile defence system.
Overnight, two rockets were knocked down by Iron Dome and others landed on open ground, Israel Radio said. By morning, air raid sirens sounded in many parts of southern Israel, local media reported.
Hamas officials in Cairo accused Israel of failing to respond to ceasefire proposals.
Israeli spokesman Mark Regev told the BBC: "I have no doubt that Hamas would be more than happy to have a temporary respite - a time out... so they could rest and re-arm and we would have missiles on Israel next week or next month. We are not interested in that."
US state department spokeswoman Victoria Nuland said Mrs Clinton - who flew into Jerusalem late on Tuesday - had held two hours of talks with Israeli Prime Minister Benjamin Netanyahu and other Israeli officials.
"They discussed efforts to de-escalate the situation and bring about a sustainable outcome that protects Israel's security and improves the lives of civilians in Gaza," Ms Nuland said.
Speaking just before the talks, Mr Netanyahu said Israel wanted a diplomatic solution but that he was ready to take "whatever action" was necessary.
"If there is a possibility of achieving a long-term solution to this problem by diplomatic means, we prefer that. But if not, then I am sure you will understand that Israel will have to take whatever actions are necessary to defend its people," he said.
Israel's Haaretz newspaper said there were divided views in the government over the truce proposals, with Defence Minister Ehud Barak in favour of accepting an Egyptian draft, while Mr Netanyahu and Foreign Minister Avigdor Lieberman were opposed.
The BBC's Jon Leyne in Cairo says both sides want more out of this than just a ceasefire. The Palestinians want a lifting of the blockade of Gaza, permanently reopening the borders. He says the hope would be that this will defuse tension and reduce pressure on Hamas.
The Israelis want an end to attacks, our correspondent says, but specifically want to prevent Hamas restocking its missiles. He says the key to that is how the Egyptians can seal the border; but this is politically sensitive among the Egyptian people and also physically difficult, as the military has a lot of trouble controlling militants in Sinai.
Israel launched its current offensive a week ago with the killing of Hamas military leader Ahmed Jabari. The Israeli government says his assassination, and the subsequent offensive, aims to end rocket fire from Gaza.
Israel has troops massed along the Gaza border but says it is holding off on a possible ground invasion as talks continue.