Gaza death toll rises as a truce effort intensifies.

Byline: Karin Laub and Yousur Alhlou

GAZA CITY, Gaza Strip -- A high-level attempt by the U.N. chief and the U.S. secretary of state to end deadly Israel-Hamas fighting was off to a rough start Monday: Gaza's Hamas rulers signaled they won't agree to an unconditional cease-fire, Israel's prime minister said he'll do whatever is necessary to keep Israelis safe from Hamas attacks and the overall Palestinian death toll surpassed 560.

Across Gaza, Israeli fighter planes hit homes and a high-rise tower, burying families in the rubble. The strike on the Gaza City tower brought down most of the building, killing 11 people -- including six members of the same family -- and wounding 40, said Palestinian health official Ashraf al-Kidra.

Israeli tanks, meanwhile, shelled a hospital in central Gaza, killing four people and wounding dozens as the daily death toll surpassed 100 for a second day. Israel said the shelling targeted rockets hidden near the compound, and accused militants of using civilians as shields.

At least 565 Palestinians have been killed and more than 3,600 wounded in the past two weeks, al-Kidra said.

On the Israeli side, seven more soldiers were killed in clashes with Gaza fighters Monday, bringing the military death toll to 25 -- more than twice as many as in Israel's last Gaza ground war in 2009.

Two civilians have also died in Palestinian rocket attacks on Israeli cities and scores of soldiers have been injured.

The mounting bloodshed brought U.N. Secretary-General Ban Ki-moon and U.S. Secretary of State John Kerry to Cairo on Monday, for a new cease-fire push. However, the gaps remain wide and no credible mediator has emerged.

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...