Tehran  - Iran's foreign ministry Monday criticised comments by US president Barack Obama of a persistent nuclear threat from Iran, saying it contradicted the new US administration's slogan of "change".

Obama presented a plan to rid the world of atomic weapons in Prague on Sunday, evoking his successful election campaign slogan of "Yes we can" to call for world action to face the nuclear threat.

He said his administration would lead a dialogue with Iran but vowed not to be soft if the effort fails. "As long as the threat from Iran persists, we will go forward," Obama said, following comments that the threat of global nuclear war had reduced, but the risk of nuclear attack had increased.

"Mr Obama was repeating the same allegation on the threat of Iran's nuclear weapon which the former (US) administration used to claim ... This has neither been approved in the (International Atomic Energy Agency) IAEA's reports nor in the US intelligence agencies," foreign ministry spokesman Hassan Qashqavi told reporters in Tehran.

"It seems repeating the same allegations of former administration is in contrary to the slogan of 'change' by the new (US) administration," Qashqavi told a news conference.

The United States and some of its European allies fear Tehran's nuclear activities along with its missile programme are covers to develop atomic weapons, meaning a missile defence shield was needed.

Tehran insists its nuclear programme is for the peaceful and scientific purposes such as generation of electricity and launching telecommunication satellites.

Obama said in the same context that the future of US plans for a controversial missile defence system in Central Europe depended on Iran.

"If the Iranian threat is eliminated, we will have a stronger basis for security and a driving force for missile defence construction in Europe will be removed," he said. (dpa)