TEHRAN: President Mahmoud Ahmadinejad, taunting the United States for trying to halt Iran’s nuclear programme, unveiled a new centrifuge on Friday which officials said would enrich uranium much faster then existing models.

U.S. President Barack Obama, who is seeking tougher U.N. sanctions against Tehran, acknowledged that such measures would not necessarily work, but said sustained world pressure could over time prompt Iran to revise its nuclear calculations.

Ahmadinejad, in a speech to mark Iran’s annual nuclear day, called the nuclear arms reduction treaty that Obama signed with Russia this week “a masquerade” hiding his true intentions.

“We consider nuclear weapons to be against humanity,” he said.

“Iran’s nuclear path is irreversible. The Iranian nation has reached a new point where no power can deter it from moving full speed ahead to reach peaceful nuclear energy.”

The head of Iran’s Atomic Energy Organisation, Ali Akbar Salehi, said the latest “third generation” centrifuges had a separation power of 10, six times that of the first generation.

The centrifuges Iran uses now are adapted from a 1970s design and have been prone to breakdowns. Tehran is known to have been testing new models for years. It was not immediately clear when the new machines would be introduced into full-scale enrichment, something analysts say would be a significant step.

“This is not unexpected and given what Obama is doing, I think they are really trying to show that they are getting past the sanctions,” said David Albright, director of the Institute for Science and International Security in Washington.

“They have been buying a lot for their centrifuge programme in the past couple of years, or trying to, and have been thwarted many times. They’ve been working on these third generation centrifuges since the early 2000s,” he said.

“The real issue is, are they able to build these in the thousands or … in the 10s, and when are they going to be installed? The other question is, do they work well?”