Heavily armed police commandos stormed a Jerusalem church compound Thursday and arrested nuclear whistle blower Mordechai Vanunu (search) for allegedly revealing classified information, seven months after he completed an 18-year prison sentence for treason, police said.

Vanunu was detained at his rented rooms in Jerusalem's St. George's church, but police spokesman Gil Kleiman declined to discuss the nature of Vanunu's alleged disclosures or to whom he made them.

Police removed papers and a computer from Vanunu's rooms, Kleiman said.

Vanunu, 49, was released from prison in April after 18 years, much of it in solitary confinement, for disclosing secrets he learned as a technician at the Israeli nuclear reactor in the southern town of Dimona (search) in the 1980s.

He has acknowledged violating his release arrangement which barred him from meeting foreigners or discussing his work at Dimona, but he said he had no more classified information to reveal.

On Thursday morning, about 20 police commandos wearing bulletproof vests and wielding machine guns burst into the walled compound of St. George's Anglican church (search) where Vanunu took sanctuary in a guesthouse after his release, arresting him as he ate breakfast.

"We were sitting ... having breakfast at nine o'clock, then all these military stormed in, running everywhere with heavy arms," said Ninni Rydsjo, a Swedish aid worker staying at the hostel attached to the church.

"They were looking outside, everywhere. We were very frightened."

While Vanunu appeared calm as he was led away, the bishop, Riah Abu El-Assal, accused Israeli police of violating the sanctity of the church, Rydsjo said.

"He was very upset. He said you don't bring weapons in here," Rydsjo said.

Vanunu was convicted in 1988 for divulging information and pictures of the Dimona reactor. The details, published in London's Sunday Times, led experts to conclude that Israel has the world's sixth-largest stockpile of nuclear weapons, including hundreds of warheads.

Israel has followed a policy of nuclear ambiguity, neither confirming nor denying it has nuclear weapons.

Vanunu, a convert to Christianity, became a hero to peace activists for his role in unveiling Israel's nuclear program.

Peter Hounam, the Sunday Times journalist who published Vanunu's nuclear revelations, said he was "horrified" by Vanunu's arrest, and accused the Israeli authorities of using Thursday's death of Palestinian Leader Yasser Arafat to try to divert attention from it.

"I think they deliberately waited until Arafat died," he told The Associated Press from England.

In an AP interview in September, Vanunu said he wanted to replace his Israeli citizenship with a foreign one, perhaps Palestinian.

"In Israel, I am regarded as a traitor ... and since my release they are not respecting my human rights, my freedom of speech or my freedom of movement," he said.

He said he planned to continue his anti-nuclear campaign, but he had no more secrets to reveal. "All I knew was published 18 years ago," he said.