By Nidal al-Mughrabi
GAZA (Reuters) - Israel killed a senior Hamas leader in an air attack on his home on Thursday, striking its first deadly blow against the top ranks of the Islamist group in a Gaza offensive that has claimed more than 400 Palestinian lives.
Nizar Rayyan, a cleric widely regarded as one of Hamas's most hardline political leaders, had called for renewed suicide bombings inside Israel. Medical officials, confirming his death, said two of his four wives and seven of his children were killed in the bombing, in Jabalya refugee camp.
Hundreds of supporters scrambling over the concrete rubble vowed revenge as the mangled bodies, covered in blood and cement dust, were extracted from the wreckage.
"The blood of Sheikh Nizar Rayyan and the blood of other martyrs will never be wasted and the enemy will pay a heavy price for the crimes it has committed," said Hamas official Ayman Taha.
Black-bearded Rayyan, 49, was a preacher at Jabalya's "mosque of martyrs" who mentored suicide bombers. With a cartridge belt around his stocky frame, he would sometimes patrol the streets of Gaza with Hamas fighters.
Hamas Radio said he had ignored advice to leave his house as other Hamas leaders have done in anticipation of assassination attempts by Israeli forces, who confirmed the air strike.
"I think that even now, after a few days of operation we have achieved changes," Israeli Foreign Minister Tzipi Livni said after talks in Paris with French President Nicolas Sarkozy.
"We affected most of the infrastructure of terror within the Gaza Strip and the question whether it's enough will be according to an assessment on a daily basis."
Israeli armoured forces remained massed on the Gaza frontier in preparation for a possible ground invasion as international calls for an immediate cease-fire mounted.
Turkey, starting a rotating membership at the United Nations Security Council, urged Israel to end the offensive and lift its blockade against the coastal strip.
A humanitarian agency said it was told Israel would let 400 foreigners leave the Gaza Strip on Friday, possibly part of preparations for a land offensive. Most resident foreigners are spouses of Gaza Palestinians and their children.
AID GETTING IN
Livni reiterated Israel's rejection of a French-proposed cease-fire of 48 hours to allow humanitarian aid into Gaza.
"There is no humanitarian crisis in the Strip, and therefore there is no need for a humanitarian truce," she said. "Israel has been supplying comprehensive humanitarian aid to the Strip ... and has even been stepping this up by the day."
Seventy trucks carrying flour, cooking oil and other humanitarian supplies, including aid from Saudi Arabia, crossed into the Gaza Strip from Israel on Thursday. But medics say their needs are acute, and power blackouts are increasing.
The deadliest conflict in the Gaza Strip in four decades has killed at least 412 Palestinians and wounded some 1,850. About a quarter of the dead were civilians, the U.N. estimates.
On the sixth day, Israeli planes and ships attacked about 20 Hamas targets, including a government complex.
Visiting southern Israeli towns where rockets fired from Gaza have killed four people since Saturday, Prime Minister Ehud Olmert said Israel was fighting Hamas with an "iron fist."
Israeli television broadcast film of rubble-strewn street in the port of Ashdod, where a Hamas rocket tore into the eighth floor of a high-rise. Several residents were treated for shock.
"I very much hope we will succeed in achieving our goals quickly," Olmert said, repeating Israel's pledge to end the rocket attacks.
In New York, the U.N. Security Council adjourned an emergency session without a vote. Western delegates described an Arab-drafted resolution demanding an immediate cease-fire as unbalanced and said talks would continue to agree a text.
The Czech premier announced that EU foreign ministers would conduct a mission to the region, likely to coincide with a visit to Jerusalem on Monday by French President Nicolas Sarkozy.
Olmert told his security cabinet on Wednesday that if a diplomatic solution could be found that ensured better security for southern Israel, the government would consider it.
Hamas leader Ismail Haniyeh said Israeli attacks must stop before any truce proposals could be considered. Israel must also lift its economic blockade of Gaza and open border crossings.
Israeli officials said a truce would require international monitoring to ensure Hamas lives up to its obligations. "At this point there's no concrete plan for monitors. It is one of several ideas being discussed," an Israeli official said.
The Gaza operation, launched after Hamas ended a six-month cease-fire on December 19 and intensified rocket strikes, could affect the outcome of Israel's February 10 national election.
A poll in the Haaretz daily showed 52 percent of Israelis favoured pursuing the attacks, with 20 percent backing a cease-fire, and 19 percent for a ground offensive into Gaza.
(Additional reporting by Adam Entous and Jeffrey Heller in Jerusalem, Patrick Worsnip at United Nations and James Mackenzie in Paris; Writing by Jeffrey Heller; Editing by Douglas Hamilton and Giles Elgood)