UNITED NATIONS — Several Western ambassadors walked out of a Security Council meeting yesterday after a Libyan representative compared Israel’s actions in Gaza to those of the Nazis in the concentration camps.

The dramatic walkout occurred during close consultations on a proposal to address the humanitarian situation in Gaza. The proposal was opposed by several of the permanent members, including America, and the South African ambassador, who serves as the rotating council president for April, ended the meeting soon after the walkout.

After the American ambassador and several other allied diplomats left the U.N. building, Syria’s ambassador, Bashar al-Jaafari, told reporters that even without hearing his Libyan colleague, Ibrahim al-Dabbashi, he agreed with the comparison. Mr. Jaafari also addressed a separate topic, sweepingly denying there were any nuclear ties between his country and North Korea.

His denial came just as CIA officials were reportedly preparing to brief Congress for the first time on the sale of a plutonium reactor to Syria. The reactor was reportedly destroyed in an Israeli air attack before becoming operational. “It is ironic that we may have already disclosed to the North Koreans more than we have disclosed to Congress,” a former American U.N. ambassador, John Bolton, said yesterday.

The Wall Street Journal and other publications cited an unnamed administration official who said that during a congressional briefing, CIA intelligence experts will report that they became convinced last year that the remote Syrian site was a nuclear facility.

Mr. Bolton, who has long advocated a public release of the intelligence by the Bush administration, said that the North Korean-built facility has apparently been erected in Syria as far back as five years ago, which is “as long as the six-party talks,” he said, referring to the American-led diplomacy with North Korea. “There is going to be an enormous reaction in Congress,” Mr. Bolton added, predicting a growing resistance to any attempt by the administration to remove Pyongyang from the list of states supporting terrorists.

“There were no Syrian-North Korean cooperation whatsoever,” Mr. Jaafari said yesterday. “We deny these rumors.”

The Syrian ambassador spoke after the comments by the Libyan deputy ambassador, Mr. Dabbasi, who is the Arab representative on the Security Council. According to several council diplomats who were present at the closed-door meeting, Mr. Dabbasi made a direct comparison between the humanitarian situation in Gaza and the Nazi concentration camps. An American U.N. ambassador, Alejandro Wolff, immediately got up, removed his interpretation earphones, and left, as did the French ambassador, Jean-Maurice Ripert, according to three diplomats who spoke on condition of anonymity. The British, Belgian, Croatian, and Costa Rican representatives followed suit.

“It was too much,” Mr. Ripert said afterward.

“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,” said a British U.N. ambassador, Karen Pierce, adding, “We support the South African presidency’s decision to close the meeting.”

But South Africa’s U.N. ambassador, Kumalo Dumisani, said he had ended the session because it became clear that no agreement over a statement would be reached. He belittled the walkout. “Ambassadors always walk out,” he said.

“Libya’s cynicism and its behavior shows there ought to be better screening before countries become members of the Security Council,” said Israel’s U.N. ambassador, Dan Gillerman. “This is what happens when you allow a terrorist state to become council member.”

America removed Libya from its list of state sponsors of terrorism after a diplomatic deal in which Libya promised to cease its weapons of mass destruction programs.

Syria’s Mr. Jaafari said he agreed with Libya’s assessment of Israel’s behavior. “We have many times compared the situation prevailing in the occupied Palestinian territories to the situation in Europe during the second World War,” he said. “Unfortunately, those who complain of being victims of some kind of genocide are repeating the same kind of genocide against the Palestinians.”