Israel continued to tighten its grip on the Gaza Strip today, as world leaders pushed for an end to the fighting that entered its 10th day.

After effectively bisecting the Gaza Strip over the weekend, the Israeli military announced that it had seized high-rise buildings and attacked tunnels at the edge of Gaza City. Further advances by the Israeli military would bring it into the heart of the Gaza’s major city.

Diplomatic efforts continued, but showed no tangible results as Israel insisted that it was justified in continuing its invasion until it was assured that Hamas, which controls Gaza, would cease its rocket fire at the Jewish state’s southern flank.

Despite the days of fierce bombings and invasion over the weekend, Hamas today continued its rocket attacks, launching more than 30 rockets at southern Israeli cities such as Ashkelon, Ashdod, Netivot and Ofakim.

European leaders continued to call for a resumption of the truce between Israel and Hamas. French President Nicolas Sarkozy met with Israeli Prime Minister Ehud Olmert and Palestinian Authority President Mahmoud Abbas, whose authority has been limited to the West Bank since his faction lost control of Gaza to Hamas in June 2007.

At a joint news conference, Sarkozy called for a cease-fire before heading for Israel.

“We in Europe want a cease-fire as quickly as possible, and that everyone understands that time is running against peace,” Sarkozy said. “The guns must fall silent, there must be a humanitarian truce.”

In Washington, President Bush again defended Israel’s actions.

“I understand Israel’s desire to protect itself,” Bush said. “The situation now taking place in Gaza was caused by Hamas.”

Bush spoke after meeting with Salva Kiir, the leader of Sudan’s troubled South. With Kiir sitting next to him, Bush spoke to reporters in remarks televised from the Oval Office.

“Instead of caring about the people of Gaza, Hamas decided to use Gaza to launch rockets to kill innocent Israelis,” Bush said. “Israel’s obviously decided to protect herself and her people.”

Bush again said he was concerned about the growing humanitarian crisis in Gaza, cut off from supplies. He said the United States was prepared to supply additional aid. Israel reported that eighty trucks loaded with humanitarian aid were transferred into the Gaza Strip via the Kerem Shalom crossing.

The violence must end, “but not at the expense of an agreement that does not prevent the crisis from happening again,” Bush said.

Meanwhile, President-elect Barack Obama continued to steer clear of foreign affairs, concentrating on the economy in Washington.

“I will continue to insist that when it comes to foreign affairs it is particularly important to adhere to the principle of one president at a time because there are delicate negotiations taking place right now and we can’t have two voices coming out of the United States when you have so much at stake,” Obama told reporters.

The toll in the Mideast continued to rise. More than 500 Palestinians have reportedly been killed — a quarter of whom are believed by the United Nations to be civilians — and at least 2,200 wounded. Five Israelis, including one soldier, have been killed.

Israel has repeatedly made three demands for ending its current campaign: It wants an end to the rocket attacks, some form of outside supervision of Hamas’ role in any cease-fire and a halt to any restocking of the group’s arsenal.

Israel has not called for an end of Hamas’ control of Gaza, though the invasion has raised questions about who will patrol the region, which was once controlled by Israel.

The heaviest fighting in Gaza was in the populated areas in the outskirts of Jebaliya. Dozens have been arrested, Israeli officials said

Military sources said that the first stage of the ground operation has progressed relatively smoothly with a relatively low level of Hamas resistance. However, that could change as Israeli forces move into the more populated areas and face greater threats.

Maj. Avital Leibovich, an Israeli military spokeswoman, said Hamas was to blame for civilian casualties because it operates in densely populated areas.

“Civilians will probably continue to get killed, unfortunately, because Hamas put them in the first lines of fire,” she said.

The bloodshed has spurred street protests around the world and brought diplomatic pressure on Israel to hold its fire.

Czech Foreign Minister Karel Schwarzenberg, heading a European Union peace mission, and French President Nicolas Sarkozy met separately with Israeli officials in Jerusalem to press for an immediate cease-fire by both sides.

“The guns must fall silent,” Sarkozy said. “There must be a humanitarian truce.”

Israeli Foreign Minister Tzipi Livni rejected the appeals, saying the military needed more time to subdue Hamas.

“We are not asking the world to take part in the battle; we are only asking to be allowed to carry it out ourselves until we reach a point in which we decide our goals have been met,” she said at a joint press conference with Schwarzenberg.

Israeli government spokesman Mark Regev said the offensive has three objectives: to “substantially destroy” Hamas’ military apparatus, break its will to fire more rockets, and bring about a new security arrangement with Egypt to prevent Hamas from bringing weapons into Gaza through the smuggling tunnels under the border.

In Washington, State Department spokesman Sean McCormack outlined a cease-fire proposal being promoted by Secretary of State Condoleezza Rice that appeared to address Israel’s conditions. He said she had discussed it by phone over the weekend with 17 foreign leaders in Europe and the Middle East.

Rice’s proposal calls for a halt to Hamas’ rocket attacks and an arrangement to deal with the tunnels. It also addresses Hamas’ main demand — ending an Israeli blockade of Gaza — by proposing a reopening of crossing points on the Israel-Gaza border.

Regev said Israeli leaders had been in contact with Rice and with Egyptian officials, but he declined to comment on her proposal. He emphasized that Israel welcomed international help to resolve the conflict, but only on Israel’s timetable.

“A cease-fire right now would be a band-aid solution,” he said. “Gaza would explode in our faces a week from now or a month from now.”

The Bush administration has accepted that argument. President Bush said Monday that the violence must be stopped, “but not at the expense of an agreement that does not prevent the crisis from happening again.”

In Damascus, Syria, a senior Hamas official rejected the U.S. proposal, the Associated Press reported. It quoted Moussa Abu Marzouk as saying the plan seeks to impose “a de facto situation” on Gaza by military force.

But the group sent a delegation to Cairo on Monday to discuss the conflict with Egyptian officials.

Israel seizes high-rises, attacks tunnels in Gaza – Los Angeles Times