Israel took nearly 70 foreign ambassadors to its border with the Gaza Strip on Wednesday as part of a diplomatic campaign to enlist international support for tougher action against the enclave's Hamas Islamist rulers.

Foreign Minister Tzipi Livni told the envoys at the Erez crossing with Gaza that cross-border rocket fire by militants had created an "unbearable" situation that would only get worse. "Israel must act in order to reduce these threats," she said.

But a large-scale military offensive in densely populated Gaza, where an Israeli blockade has already fuelled fears of a humanitarian crisis, could prove a tough sell for Israel.

Ramiro Cibrian-Uzal, the ambassador of the European Union to Israel, condemned the rocket fire and called for it to stop immediately and unconditionally. Shortly after diplomats left the much-bombarded town of Sderot, a rocket hit a house there.

But the EU envoy told Reuters after the tour: "The European Union does not consider a large military operation in Gaza to be a good idea and we do not believe it will bring a permanent solution to the problems Israel is confronted with."

Only last month, Israel backed down after an international uproar over fuel cuts to Gaza's main power led to blackouts.

Prime Minister Ehud Olmert has so far been wary of launching a major ground operation, which could cause heavy casualties, arguing there were no "overnight solutions" to daily rocket fire from Gaza that has inflamed Israeli public opinion.

But he faces growing domestic pressure after Hamas claimed responsibility for a suicide bombing in southern Israel last week and an 8-year-old Israeli boy lost part of his leg to a rocket strike in Sderot on Saturday. Olmert, who visited Germany to seek support over Gaza, says Israel is at "war".

Israel says it can maintain parallel tracks with the Palestinians, one aimed at breaking Hamas's hold on Gaza, and the other aimed at reaching a statehood agreement with West Bank-based Palestinian President Mahmoud Abbas, whose Western-backed forces were defeated by Hamas in Gaza last year.

INTERNAL DEBATE

The rockets have sparked debate inside and outside Olmert's government, with top ministers calling for the army to assassinate Hamas political as well as military leaders and to flatten those areas in Gaza where the rockets are launched.

Prize-winning Israeli author Amos Oz, in a letter published on the front page of the mass market daily Yedioth Ahronoth, appealed to Israeli leaders to think through the implications.

"The number of casualties from a land invasion into Gaza will be much greater than the number of casualties from 7 years of Qassams," the noted peace campaigner said of the rockets.

Frequent Israeli air strikes and ground incursions into the Gaza Strip have killed some 300 Palestinians in the past year, including dozens of civilians, but failed to prevent rocket fire, which killed two Israelis in the same time period.

Shunned by the West for refusing to renounce violence after beating Abbas's Fatah faction in a parliamentary election two years ago, Hamas says it would cease fire if Israel stops its military operations in Gaza and the occupied West Bank.

Hamas is also demanding an end to an Israeli-led blockade that has cut supplies to the territory's 1.5 million people.

Although Abbas's Fatah faction remains deeply hostile to Hamas following its seizure of the Gaza Strip in June, the president and his West Bank-based government have publicly criticized Israel for stepping up its military action and threats to kill Hamas leaders.

Israel denied involvement on Wednesday in the killing in Damascus of Imad Moughniyah, a senior commander in the Lebanese Hezbollah movement which has links with Hamas. Hezbollah, Hamas and their ally Iran all blamed Israel and Hamas warned it would retaliate if Israel assassinated any of its leaders in Gaza.