Iranian President Mahmoud Ahmadinejad has told a conference in Tehran questioning the Holocaust that Israel's days are numbered.

"Just as the USSR disappeared, soon the Zionist regime will disappear," he said to the applause of the participants.

The two-day conference provoked widespread international outrage.

German Chancellor Angela Merkel condemned the forum and British Prime Minister Tony Blair called it "shocking beyond belief".

Iran said it wanted to debate what it called taboos surrounding the Holocaust.

The BBC's Frances Harrison in Tehran said the conference was like a roll call of the world's most infamous Holocaust deniers - all delighted that Iran had given them the oxygen of publicity.

'Free forum'

"The trend for the existence of the Zionist regime is downwards and this is what God has promised and what all nations want," President Ahmadinejad said.

"Whether the Holocaust occurred or did not or whether it had vast dimensions or not, it has become a pretext to create a base for aggression and threats for the countries of the region," he said.

Mr Ahmadinejad urged the participants - including ultra-Orthodox Jews who say the creation of Israel was an abomination - to examine Holocaust in more detail.

"Iran is your home and is the home of all freedom seekers of the world. Here you can express your views and exchange opinions in a friendly, brotherly and free atmosphere," he said.

Iran, which is home to 25,000 Jews, says 67 researchers from 30 countries attended the meeting.

Participants included a number of well-known "revisionist" Western academics.

Iranian Foreign Minister Manouchehr Mottaki said on Monday the aim of the conference was "not to deny or confirm the Holocaust", but "to create an opportunity for thinkers who cannot express their views freely".

In a number of European countries - including Germany, Austria and France - it is illegal to deny the Holocaust. An Austrian court jailed Briton David Irving for three years on charges of Holocaust denial.

'Unacceptable character'

In London, Mr Blair called the Holocaust conference "shocking beyond belief".

He described Iran as a "major strategic threat" to the Middle East.

In Berlin, Ms Merkel - flanked by visiting Israeli Prime Minister Ehud Olmert - said: "We reject in the strongest terms conferences held in Iran on the supposed non-existence of the Holocaust.

"Germany will never accept this and will use all possibilities at its disposal to oppose it."

Mr Olmert said the conference showed the "unacceptable character" of the Iranian government and the "danger" it poses for the West.

Mr Ahmadinejad has repeatedly downplayed the extent of the Holocaust, describing it as a myth used to justify the existence of Israel and oppression of the Palestinians. He has called for an end to the Israeli state.

Many Iranians must be wondering why they have the right to deny the Holocaust with impunity, but not to question their own leaders without risking jail, our correspondent says.

In recent months, newspapers have been closed, journalists jailed and students penalised for engaging in any sort of political activity in Iran.

Photo Caption

Iranian president Mahmoud Ahmadinejad (left) shakes hands with an anti-Zionist rabbi in Tehran