GAZA CITY, Gaza Strip (AP) -- Israeli airstrikes pummeled a wide range of targets in the Gaza Strip on Tuesday as the U.N. chief and the U.S. secretary of state began an intensive effort to end more than two weeks of fighting that has killed at least 570 Palestinians and 29 Israelis.
Overnight, Israel bombed five mosques, a sports complex and the home of the late Hamas military chief, a Gaza police official said.
The Israel military announced early Tuesday that two more soldiers had died, one from sniper fire on Monday and one from still unexplained causes, bringing the military death toll to 27. It's the highest number of Israeli military fatalities for any campaign since the 2006 Lebanon war. Two Israeli civilians have also been killed in the latest conflict.
The Israeli campaign, launched July 8, is aimed at stopping Hamas rocket fire into Israel -- some 2,000 rockets have been launched over the past two weeks, the military says -- and destroying tunnels the military says Hamas has constructed from Gaza into Israel for attacks against Israelis.
The airstrikes set off huge explosions that turned the night sky over Gaza City orange early Tuesday. The sound of the blasts mixed with the thud of shelling, often just seconds apart, and the pre-dawn call to prayer from mosque loudspeakers.
The strikes came as U.N. chief Ban Ki-moon and U.S. Secretary of State John Kerry met in Cairo late Monday to launch the highest-level push yet to end the deadly conflict. The U.N. has said that the majority of the Palestinians killed were civilians, among them dozens of children.
In the Gaza Strip, Israeli aircraft hit more than 70 targets, including the home of the late leader of Hamas' military wing, five mosques and a sports complex, said Gaza police spokesman Ayman Batniji. There were no casualties in the mosques or at the sports complex, which includes a gym, three martial arts studios and a soccer field.
Tank shells also damaged several houses along the eastern border of the territory, he said. At least 19 fishing boats were burned by Israeli navy shells fired from the Mediterranean Sea, Batniji added.
Six upper floors of a Gaza high-rise collapsed onto the two lower stories, buckling them into rubble. At the scene, construction company owner Ehab Batch, 40, and several of his workers were trying to retrieve documents from what had once been the company's 2nd floor offices.
Batch, who said he had had no work in the past year because Egypt had blocked border tunnels that bring in construction material, said Gaza needs an immediate cease-fire and a deal that would open all border crossing points.
"We need Gaza people to have a (normal) life, as all the people in the world," Batch said.
Among the facilities hit overnight were three homes, including one where three women from the same family perished, according to Gaza health official Ashraf al Kidra.
But prospects for a truce remained elusive.
Egypt, Israel and the U.S. back an unconditional cease-fire, to be followed by talks on a possible new border arrangement for Gaza. Israel and Egypt have severely restricted movement in and out of Gaza since Hamas seized the territory in 2007.
Hamas, with some support from Qatar and Turkey, wants guarantees on lifting the blockade before halting fire. The Islamic militant group has no faith in mediation by Egypt's rulers, who deposed a Hamas-friendly government in Cairo a year ago and tightened restrictions on Gaza -- to the point of driving Hamas into its worst financial crisis since its founding in 1987.
The top Hamas leader in Gaza, Ismail Haniyeh, said Monday that Gaza's 1.7 million people share Hamas' goal of forcing Israel and Egypt to lift the blockade.
"We cannot go back, we cannot go back to the silent death" of the blockade, he said. "Gaza has decided to end the blockade by its blood and by its courage."
After a meeting with Egyptian Foreign Minister Sameh Shukri, Ban said that "violence must stop by all sides," and that they must enter negotiations, apparently siding with Cairo's approach.
"We can't claim victory simply by returning matters to where they stood before they led to terrible bloodshed," Ban said.
The border blockade has set Gaza back years, wiping out tens of thousands of jobs through bans on most exports and on imports of vital construction materials Israel says could be diverted by Hamas for military use. Israel allows many consumer goods into Gaza, but experts say Gaza's economy cannot recover without a resumption of exports.