The US says it's "another provocative step" and it's hard to disagree with that.

BBC:

The IAEA released a report each quarter detailing its progress at monitoring Iran's nuclear development.

The BBC obtained a copy of the latest report, which has not yet been officially released.

It concludes: "The director general is unable to report any progress on the clarification of outstanding issues including those relating to possible military dimensions to Iran's nuclear programme."

It adds that despite intensified dialogue with Iran, no progress has been made on how to clear up the questions about Iran's nuclear work.

The IAEA has made similar complaints in previous quarterly reports, and Iran is under an array of sanctions as a result of its lack of co-operation.

Iran had informed the IAEA in a letter on 23 January that it planned to introduce a new model of centrifuge called the IR2m, which can enrich two or three times faster than current equipment.

Gas centrifuges are used to increase the proportion of fissile uranium-235 atoms within uranium.

For uranium to work in a nuclear reactor it must be enriched to contain 2-3% uranium-235 while weapons-grade uranium must contain 90% or more uranium-235.

Israeli Prime Minister Benjamin Netanyahu said the new centrifuges could cut by a third the time Iran, one of Israel's fiercest opponents in the Middle East, needed to create a nuclear bomb.

The new centrifuges will be installed at their main enrichment plant in Nantanz, which is where all their highly enriched uranium is stored. It wouldn't take long to enrich that HEU from its current 20% to the 90% necessary to build a bomb.

Netanyahu is right. The new centrifuges are a qualitative step forward for Iran's nuclear program and telescopes the time left to make a decision on what to do about it.