Gaza/Tel Aviv - Israel edged closer Thursday toward a ground invasion of the Gaza Strip, but also intensified contacts with foreign leaders seeking a diplomatic solution to the Gaza crisis.

Foreign Minister Tzipi Livni traveled to Paris to discuss "different ideas about what can be done on the diplomatic level" with French President Nicolas Sarkozy, said Yigal Palmor, a senior advisor to Livni.

Palmor would not confirm that one idea being raised was the deployment of international monitors to ensure compliance with any new truce in the Gaza Strip.

He said Israel was "very seriously" examining a number of proposals "from various parties who want to contribute." It was demanding "clear guarantees and a mechanism" that would restore calm to residents of southern Israeli towns and cities hit by Palestinian rockets from Gaza.

While its ground troops were ready along the Gaza border, awaiting orders for any ground operation to start, Israel kept up its relentless air raids on the sixth day of its offensive against Hamas.

The Israel Air Force destroyed the house of a senior Hamas leader in northern Gaza, killing him, his wife and his eight children, hospital officials said.

Nizar Rayan's house was reduced to its bare concrete core, its front and top floors completely ripped off, leaving gaping holes that exposed the inside of those lower-level rooms still standing. Hundreds of onlookers gathered outside as rescuers carried the bodies to ambulances.

Rayan, in his 50s, was the most senior Hamas leader killed so far in the Israeli offensive. Most top leaders of the movement ruling Gaza have gone into hiding.

He was close to Hamas' armed wing, the al-Qassam Brigades and led it and other Palestinian fighters in opposition to several Israeli forays into the Gaza Strip in the past.

An Israeli military spokeswoman in Tel Aviv confirmed Rayan had been the target of the airstrike, saying Rayan had been involved in several attacks against Israeli civilians, including a March 2004 double suicide bombing in the Israeli port city of Ashdod.

She said Rayan had personally sent one of his sons to carry out a 2002 suicide attack in a former Jewish settlement in northern Gaza. One of the more extremist leaders within Hamas, he had been advocating a renewal of suicide bombings in Israel, she said. The strike meant the overall Palestinian death toll of the six-day offensive reached at least 410, with some 2,000 injured. Four Israelis - three civilians and a soldier - have also been killed.

Other targets hit Thursday were the Palestinian parliament building in Gaza City, the Hamas-run Justice Ministry and more tunnels running under the Gaza-Egyptian border.

Hamas, for its part, also kept up its attacks, with a barrage of at least 15 rockets striking southern Israeli towns and cities, including Ashdod, Ashkelon and Beersheba.

One scored a direct hit on an eight-storey residential building in Ashdod, penetrating the roof and two floors, firefighters said. They said they quickly evacuated the building for fear part of its might collapse, but that no one was hurt.

A senior Israeli military official told Israel Radio the Israeli ground operation, which is believed imminent, would involve many soldiers. But he said it would be relatively limited in scope.

And the Israel Defence Forces' (IDF) official spokesman, Brigadier General Avi Benyahu, stressed its aim would not be to reconquer the Gaza Strip, nor to topple the Hamas regime.

Israel's offensive had already delivered a "harsh blow" to Hamas' rocket arsenal and launching site, but would not be able to destroy every single rocket.

Israel was therefore not as much acting against the rockets, as "against the motivation of Hamas to fire them," he told Israel Army radio, warning the operation would "take time."

Amid the feverish diplomatic efforts, Palestinian President Mahmoud Abbas will travel to New York this week, heading a high-level Arab delegation with the aim of getting the UN Security Council to call a ceasefire in the Gaza Strip.

Yasser Abed Rabbo told a news conference in Ramallah that Abbas will be in New York when the Security Council meets to discuss an Arab proposal calling for a halt to Israeli air attacks on the Gaza Strip.

"We will stay in New York until we get a ceasefire, no matter how long it will take," he said.

He said Abbas wants to see an end to the Israeli attacks and wants to see all the Palestinians united behind a decision to halt the fighting and observe a new truce.

Israel's caretaker Prime Minister Ehud Olmert, in Beersheba, vowed to continue to hit Hamas with an "iron fist," saying Israel was "unable to live with" the daily rocket and mortar attacks at its south. He added he hoped Israel would be able to achieve the goals of its offensive "as quickly as possible."

His spokesman Mark Regev, said Israel was, in the mean time, "engaging with friends abroad" on the "common goal" of ending rocket attacks on its southern region. Asked whether Israel was debating the placement of international monitors, he said: "at the moment, it is like putting the cart before the horse."

Palmor said Israel was not "negotiating through the press" nor making any specific prerequisites" at this point about the kind of international guarantees it was seeking for an end to the Hamas rocket attacks. (dpa)