UNITED NATIONS — U.S. whistleblower Daniel Ellsberg says Mordechai Vanunu should be awarded the Nobel Peace Prize for revealing Israel’s nuclear arsenal and be allowed to travel the world to promote the abolition of nuclear weapons.

Ellsberg, whose disclosure of secret Pentagon documents about the Vietnam war helped crystallize anti-war sentiment in the United States in the early 1970s, urged delegates from 188 countries attending a conference to review the Nuclear Nonproliferation Treaty to strongly protest Israel’s restrictions on Vanunu’s speech and travel and his likely return to prison.

Vanunu, a former technician at Israel’s nuclear plant in the southern town of Dimona, served 18 years in prison for divulging information about Israel’s secretive atomic program to a British newspaper in 1986. He has been barred from leaving the country until at least April 2006 and went on trial last month for allegedly violating a condition of his 2004 release that banned contacts with foreigners.

Ellsberg, who said he recently spent five days with Vanunu in Israel, dismissed the government’s claim that Vanunu still has secrets that could endanger national security as “absurd.”

“It’s clearly an attempt to prolong his sentence indefinitely, sending him back to prison for years,” Ellsberg told reporters Wednesday before addressing the review conference.

“The message this sends to potential Vanunus in other states is very clear, and the question at this conference is whether the nations of the world should encourage or strongly protest that message,” he said. “The fact is more Vanunus are urgently needed in this world.”

Ellsberg said that if, for instance, an Indian technician had revealed the country’s plan for a nuclear test, international pressure might have prevented it — and “how much better India, Pakistan and the world would be.”

In the early 1960s, Ellsberg said he was working in the Pentagon on command and control of nuclear weapons and nuclear war plans and should have done what Vanunu did and “tell my country and the world the insanity and moral obscenity of our war planning, which remains the same today.”

“I regret profoundly that I did not reveal that fact publicly, with documents,” he said.

Ellsberg, who spoke on behalf of the non-profit Nuclear Age Peace Foundation, which promotes the abolition of nuclear weapons, said Israel today is probably the third or fourth-largest nuclear state — behind the United States and Russia, and possibly France.

He said Vanunu is reported to have revealed in 1986 that Israel had about 200 nuclear weapons. Vanunu has estimated that at the same rate of production Israel had when he left Dimona in 1985, the country should have close to 400 weapons today, Ellsberg said.

That’s more than Britain, China, India and Pakistan, and probably more than France, he said.

Israel neither acknowledges nor denies having a nuclear weapons program, following a policy of nuclear ambiguity.

Ellsberg said British nuclear scientist Joseph Rotblat, who won the 1995 Nobel Peace Prize for his work against nuclear weapons with the Pugwash Conferences on Science and World Affairs, has repeatedly nominated Vanunu for the award.

“He should get the Nobel Peace Prize as Joseph Rotblat has frequently recommended,” he said.