"What Iran is doing is pure vanity," said Gaddafi. "If a decision is taken against Iran, it will suffer the same fate as Iraq... Iran is no stronger than Iraq and will be unable to resist."

Gaddafi was referring to the 2003 U.S. invasion of Iraq, an attack Washington said was intended to rid Iraq of weapons of mass destruction.

Iran is refusing to back down in a row with major powers over its civilian nuclear activities which the West says is a cover for a secret programme to build atomic warheads. Tehran says its only goal is to produce electricity.

Pressure has grown for deeper United Nations sanctions against Iran after an informal deadline for it to freeze expansion of nuclear work passed this weekend.

Gaddafi, whose relations with the West improved when Libya scrapped its weapons of mass destruction programmes in 2003, said countries that chose isolation were doomed to fail.

"No country will survive on its own in the future -- it will disappear," Gaddafi said. "The challenges facing Iran are greater than its ability to overcome them alone."

The future was with regional groups of states such as the African Union and European Union, Gaddafi said during a visit to neighbouring Tunisia.

Gaddafi took power in 1969 in a military coup in his oil producing North African state and was shunned for decades by the West, which accused him of supporting terrorism.