Vanunu, who walked out of the Shikma prison in the Israeli town of Ashkelon on Wednesday, where he was imprisoned for 18 years, said Western leaders such as US President George Bush, Tony Blair, Gerhard Schroeder and Vladimir Putin should "speak up" on Israel's nuclear secrets.
"Israel doesn't need nuclear weapons, especially now that all of the Middle East is free from nuclear arms. My message today to all the world is open the Dimona reactor for inspections," he said.
Vanunu was jailed in 1986, reportedly for treason, after disclosing information to Britain's Sunday Times newspaper which led analysts to conclude Israel had produced more than 100 nuclear warheads.
The 49-year-old former nuclear technician told a crowd of journalists and supporters at the prison's gates that he was "kidnapped by Israeli spies in an apartment in Italy in September 1986, drugged and then kept on a yacht for seven days, chained to a bed", before being brought to Israel, where he was imprisoned in October the same year.
'Proud and happy'
Vanunu, who was "proud and happy at what he had done", said he had "no more secrets". "I am very glad that I succeeded to do what I did. I don't have any secrets... since the article was published there are no more secrets".
He said Israel's Mossad spy agency and Shabak (domestic intelligence), also known as the Shin Bet security services, "did not succeed in breaking me … to make me crazy".
"I am a symbol that a free spirit can survive. Nobody can destroy the will of the man who wants to be free. You cannot destroy the human spirit"
former Israeli nuclear technician
"I suffered cruel, barbaric treatment by Israeli spies Mossad, Shabak agents. The guards inside the prison were only obeying orders from Shabak, Mossad", Vanunu said.
He added: "I suffered for 18 years in solitary confinement because I am a Christian. If I was Jewish I would not have had this suffering."
"I am a symbol that a free spirit can survive. Nobody can destroy the will of the man who wants to be free. You cannot destroy the human spirit."
Questioned on his statements made to security officers in a videotape aired by Israeli media, Vanunu reiterated that "I don't think we need a Jewish state" and added "the Jewish state needs to solve its problems with the Palestinians".
Israel has slapped severe restrictions upon Vanunu's release, including that he is not allowed to leave Israel for a year, approach border exits or talk to foreign nationals without prior approval for at least six months.
Dimona plant where Vanunu
worked before being sacked
Vanunu's release was delayed after he apparently refused to give details of his place of residence once he is set free.
Israel has kept the nuclear reactor in Dimona - where Vanunu worked for nine years until he was fired in 1985 - closed to international inspection.
Vanunu, who said he wished to start a new life in the United States, thanked "all my friends for supporting me". He said they are "heroes".