DUBAI: Ten years after the US-led invasion on Iraq, ex-UN inspector Hans Blix has urged world powers to avoid committing the same error by going to war against Iran based on fears it is developing nuclear weapons.

World "memories are short," the now 82-year-old Swedish ex-diplomat told a small group of journalists, including AFP, at a press gathering in Dubai.

"Memories of the failure and tragic mistakes in Iraq are not taken sufficiently seriously," he said.

"In the case of Iraq, there was an attempt made by some states to eradicate weapons of mass destruction that did not exist, and today there is talk of going on Iran to eradicate intentions that may not exist. I hope that will not happen."

Blix, former chief of the International Atomic Energy Agency (IAEA), led the UN weapons inspection team in Iraq from March 2000 to June 2003, charged with finding the WMD that London and Washington were convinced former Iraqi dictator Saddam Hussein was concealing.

Such weapons were never found, undermining the entire rationale for a conflict that left thousands of Iraqis and foreign soldiers dead.

Author of the book "Disarming Iraq", Blix had repeatedly called for further inspections before launching a war on Iraq.

Following the 2003 invasion, the White House dispatched a team of 1,000 inspectors who failed to find any prohibited weapons.

Today, Blix believes that the international community has even less evidence of the existence of atomic weapons in Iran, which is facing international pressures over its controversial nuclear programme.

"It is true that diplomatic negotiations have dragged over the years with little results so far... Some people assume that a war action will solve the problem," said Blix.

"I think others should examine what is the merit of that and find that there is much more demerit," he said, adding that "a war could develop into a terrible conflagration in the region."

"If Iran has not made up its mind to make weapons of mass destruction before a war, I think they will come to that conclusion after a war," said Blix, who wants international pressure on Iran to be eased.

"Threats can back up diplomacy but threats can also undermine diplomacy," he said.

The United States and Israel accuse Tehran of masking a weapons programme under the guise of a civilian atomic drive, charges Iran denies.

US President Barack Obama's policy on Iran has stressed sanctions and covert sabotage while playing down possible military action.

However Israel, the region's sole if undeclared nuclear power, has repeatedly warned it cannot rule out a military strike to prevent Tehran gaining the ability to produce a nuclear weapon.

Blix believes Iran gave "positive signals" during last week's meetings with world powers -- the United States, China, Russia, Britain, France and Germany, known as the P5+1.

During the talks in Kazakhstan, the world powers put forward a proposal to ease biting sanctions if Tehran halts the sensitive work of enriching uranium.

Michael Elleman, senior fellow for regional security cooperation at the International Institute for Strategic Studies (IISS), says the Islamic republic has taken a "very positive step ... by converting the 20 percent uranium into fuel plates for the research reactors."

According to him, the Iranians have not yet taken any "substantive steps to weaponise the uranium they are enriching now or to militarise the programme."

But "they are building more and more capacity to do it and do it relatively quickly," said Elleman.

Nevertheless, with the talks in Kazakhstan's financial capital Almaty, "there is some reason to be slightly optimistic, more than six months ago."