Israel found itself isolated Friday in an open debate in the Security Council on its rejection of a UN fact-finding mission to the Palestinian refugee camp in Jenin.

Only the United States offered any kind of relief to Israel, declaring that, contrary to Palestinian claims, "there is as yet no evidence that a massacre occurred in Jenin."

But deputy US ambassador James Cunningham said it was "regrettable" that Israel had decided not to cooperate with the fact-finding team set up by UN Secretary General Kofi Annan.

And State Department spokesman Richard Boucher said there were "unanswered questions" that still need answers, while highlighting efforts to provide humanitarian aid to the area.

A total of 38 speakers took part in the six-hour debate.

Nasser Al-Kidwa, Palestinian observer to the UN, said the council had failed to give Annan its full support and had caved in to "blackmailing" by the Israeli government, which repeatedly objected to the team's composition and terms of reference.

"Israel's refusal to cooperate with the mission proves that its defence forces committed unspeakable atrocities against our people in the Jenin refugee camp," Al-Kidwa said.

Israel's ambassador, Yehuda Lancry, recounting his government's reasons for challenging the mission, said the council turned a blind eye to the Israeli civilian victims of terrorist attacks.

Lancry accused the Palestinians of deliberate misinformation, of making "over-alarmist" statements and exaggerating the number of casualties in the nine-day battle for Jenin.

Meanwhile the United States struggled to explain its concept of a Middle East peace conference planned for the summer, with officials downplaying expectations.

They said Washington feared unrealistic hopes had been raised by banner front-page headlines about Secretary of State Colin Powell's Thursday announcement of the talks.

"The exact modalities are being developed," White House spokesman Ari Fleischer said. "The meeting is going to be a very helpful way to explore a variety of ideas that different people have for how to bring peace to the region.”