Diplomats said the comments came in a speech by Libya's deputy permanent U.N. representative Ibrahim Dabbashi, who also holds the title of ambassador.

"The Libyan ambassador compared the situation in Gaza to the Nazi Holocaust," said a Western diplomat who was present at a council discussion on the Middle East. "Afterwards, the Western envoys stood up and left the room in protest."

Among the chief diplomats who left the council chamber were the U.S., French, British, Belgian and Costa Rican envoys, diplomats said. Some others remained.

The remark came during a discussion on a draft statement proposed by Libya and some other countries that would have expressed serious concern about the humanitarian situation in Gaza.

South Africa's Ambassador Dumisani Kumalo, currently president of the 15-nation council, closed the meeting after the walkout. He told reporters the council had again failed to reach an agreement and would return to the issue later.

British official Karen Pierce said: "A number of Council members were dismayed by the approach taken by Libya and do not believe that such language helps advance the peace process."

Such protests against fellow members of the Security Council are quite rare, diplomats said.

"We try to be tolerant when it comes to different views, but there are limits," a council diplomat told Reuters.

In January, Israel sealed border crossings with the Gaza Strip in response to Palestinian rocket attacks against southern Israel.

The United Nations has warned this has resulted in a humanitarian crisis for the territory's 1.5 million people, most of whom depend on foreign aid.

Six million Jews were systematically murdered by Nazi Germany during World War II in the Holocaust.