.hurriyet2008-detailbox-newslink { font-family: Arial, Helvetica, sans-serif; font-size:13px; font-weight:bold; text-decoration:none; color:#000000;}.hurriyet2008-detailbox-newslink:hover { font-family: Arial, Helvetica, sans-serif; font-size:13px; font-weight:bold; text-decoration:underline; color:#990000;}ISTANBUL - Israeli troops tighten their military grip on the Gaza Strip with new airstrikes and ground battles and its defense minister says the deadly offensive in the besieged Palestinian enclave will go on until Israel is safe.

Israeli forces pounded Gaza Strip houses, mosques and smuggling tunnels yesterday from the air, land and sea, killing at least 13 civilians, including seven children and the defense minister said the offensive in the Palestinian enclave would go on until Israel was safe.

International efforts to secure a cease-fire moved ahead with French President Nicolas Sarkozy, top EU diplomats and Middle East Special Envoy Tony Blair visiting the region, but they seemed able to offer little beyond words. Israeli foreign minister rejected calls for an immediate truce to the Gaza war, saying Israel was aiming to change the "equation in this region."

"We are fighting with terror and we are not reaching an agreement with terror," Tzipi Livni said, in reference to the Islamist Hamas rulers of the Gaza. "When Israel is being targeted, Israel is going to retaliate," she said, according to Agence France-Presse.

Despite the mounting deaths in Gaza, Israeli Defense Minister Ehud Barak said the campaign would continue until Israel achieved "peace and tranquility" for residents of southern Israel. Gaza's Hamas strongman urged Palestinians to "crush" the invading Israeli forces and target Israeli civilians.

"Hamas has sustained a very harsh blow," Barak told parliament's foreign affairs and defense committee "But we still haven't reached our objectives, so the offensive continues."

Increasing casualties
Gaza health officials reported 537 dead and nearly 2,500 wounded since Israel embarked upon its military campaign against Gaza's Islamic Hamas rulers on Dec. 27. Some 200 civilians were among the dead, they said. A total of 13 civilians died in the various attacks across Gaza yesterday morning, Gaza health official Dr. Moaiya Hassanain told The Associated Press.

Four young siblings were killed in a missile strike on a house east of Gaza City. Three other children died in a naval shelling of a Gaza City beach camp, and three adults died when a missile struck near a house of mourning in the northern town of Beit Lahiya, he said. Three other adults died in attacks elsewhere.

Five Israelis have been killed since the offensive began, including one soldier killed in the ground operation. Three civilians and another soldier were killed by rocket fire.

A military spokeswoman said the air force bombed more than 30 targets, including homes of Hamas members used as weapons depots, tunnels and a suspected anti-aircraft rocket launcher. Israel's advances into Gaza have carved the 40-km long coastal territory, home to 1.5 million people, into two zones and forces have surrounded its largest urban area, Gaza City

A Hamas official said a delegation from the Islamist group would head for talks in Egypt, which has also opened contacts to achieve a ceasefire. But senior Hamas political leader Mahmoud Zahar urged Hamas forces to fight on "in the name of God," reported Reuters. The armed wing of Hamas, meanwhile, said yesterday that it has "thousands" of fighters ready to battle Israel in Gaza, in a second defiant televised address.

Meanwhile, Czech Foreign Minister Karel Schwarzenberg, heading an EU peace mission, could offer her little comfort. "We do not have a specific plan for a ceasefire because the ceasefire as such much be concluded by the involved parties," he said in Jerusalem.

Former British Prime Minister Tony Blair, envoy for a major powers group called the Quartet, said a ceasefire was a priority. "We are doing everything we possibly can to bring about an end to a situation of immense suffering and deprivation," he said after meeting Palestinian President Mahmoud Abbas in the West Bank.

The Quartet wanted an immediate ceasefire respected by all sides and to get humanitarian aid flowing into Gaza, former British PMsaid.

French President Nicolas Sarkozy said he "condemned this offensive" for distancing chances for peace and making it harder to get aid to Palestinians in Gaza. He met Egyptian President Hosni Mubarak and headed for meetings in Israel and the Palestinian territories.