President Mahmoud Ahmadinejad has said Iran will try to achieve nuclear capability as soon as possible.

His comments, reported by Iran's Isna news agency, come as a UN deadline for Tehran to freeze its uranium enrichment programme expires.

For the first time, a political party in Iran has called on Mr Ahmadinejad to accept the UN's demands.

Iran denies Western claims that it is seeking nuclear weapons, saying its programme is for purely peaceful ends.

A UN resolution, adopted on 23 December 2006, imposed sanctions against Iran's nuclear and missile programmes and opened the way for further measures if it failed to halt uranium enrichment within two months.

Following the deadline's expiry on Wednesday, the UN's International Atomic Energy Agency (IAEA) nuclear watchdog is expected to report that Iran has defied the 60-day ultimatum to suspend its activities.

Iran resumed uranium enrichment last year. The process can produce fuel for power stations or, if greatly enriched, material for a nuclear bomb.

Signs of dissent

Speaking in the northern town of Siahkal, Mr Ahmadinejad said Iran was determined to acquire nuclear capabilities, even to the exclusion of everything else.

 "We... will continue our work to reach our right [to nuclear technology] in the shortest possible time," Isna quoted Mr Ahmadinejad as saying.

"Obtaining this technology is very important for our country's development and honour. It is worth it to stop other activities for 10 years and focus only on the nuclear issue."

But one small radical reformist political party, the Islamic Revolutionary Mujahadin Organisation, has complained that Iran's drive to produce nuclear energy has endangered national security, the national interest and the destiny of the Iranian people.

"The [Iranian] officials should open talks before [UN] Resolution 1737's deadline runs out and accept its sensitive requirements to prevent the adoption of new resolutions against our country," the party was quoted by AFP news agency as saying.

"This nation has other more important and undeniable rights which should not be sacrificed for this one," it said in a statement.

The party asks why Iran needs to produce the fuel for one power plant that has not even been completed yet.

The BBC's Frances Harrison says this is the first time there has been open criticism of Mr Ahmedinejad's nuclear policy.

Allies of the president in parliament were quick to say it came from lackeys of the United States who did not even know the basics of politics, our correspondent adds.

Earlier, Iran's top nuclear negotiator Ali Larijani said the issue could only be resolved through dialogue, not force.

"Anybody interested in non-conventional or illogical, irrational [moves] would definitely receive an appropriate response," he said after meeting IAEA chief Mohamed ElBaradei in Vienna.

But he said Iran was looking "for ways and means to start negotiations".

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