Israel's Supreme Court upheld on Monday security restrictions placed on nuclear whistleblower Mordechai Vanunu (search), limiting his movements and the things he is allowed to say.

Vanunu completed an 18-year prison term in April, but Israel's security establishment decided the man who revealed Israel's nuclear secrets would not be allowed to leave the country or speak to the foreign media, saying he still has state secrets to reveal.

Vanunu's movements around seaports and airports have also been restricted.

The Supreme Court ruled the restrictions were necessary because Vanunu could reveal more state secrets.

"We are saying always that Israel is not a real democracy, and today we are seeing it inside the Supreme Court," Vanunu told reporters after the ruling. "We will find a way to continue to survive and demand the rights to live as best we can."

Vanunu spoke outside the courtroom to a swarm of journalists from Israel and abroad. It's not clear if that in itself violated the restrictions, which prohibit Vanunu from initiating contact with foreigners.

A lawyer for the state prosecutor's office, Shai Nitzan, said the state had begun a criminal investigation against Vanunu for allegedly violating several of the restrictions, including interviews he granted to foreign media.

A measure preventing Vanunu from traveling abroad for a year could be extended if the state determines that Vanunu has violated the restrictions, Nitzan said.

Vanunu said he wants to live abroad and insists he has no more state secrets to reveal.

"My country is not Israel. My country is outside of Israel. Israel didn't respect me for 18 years. For 18 years, Israel condemned me as a traitor, as a spy. I don't like Israel, I don't want to live in Israel. I want to be free and to leave Israel," Vanunu said.

Many Israelis despise the Moroccan-born Israeli for a 1986 interview with London's Sunday Times that included pictures and details of Israel's nuclear reactor in the desert town of Dimona (search). Vanunu had worked there as a technician.

Israel has a policy of "ambiguity" regarding its nuclear arsenal, refusing to confirm or deny its capabilities.

But evidence Israel has nuclear arms is overwhelming, much of it based on the pictures and information leaked by Vanunu. Experts say Israel may have as many as 300 warheads as well as the capability of building more quickly.

Vanunu said he is considering further legal action. He could request the three-judge Supreme Court panel be expanded to hear the case again, even though such appeals are often rejected.

Vanunu said he would continue to live in St. George's Cathedral, a church not far from Jerusalem's Old City, explaining that he feels more comfortable among Palestinians and foreigners.

Vanunu, who is now a prominent figure in the international anti-nuclear weapons movement, also criticized a recent visit to Israel by Mohamed ElBaradei (search), the head of the United Nations nuclear watchdog.

"I am very disappointed by Mr. Baradei because I expected him to go and inspect the Dimona reactor," Vanunu said. "The job of Mr. Baradei is to go and see if what I said ... if it's true.