Iran and world powers will resume talks next month in New York on reaching a long-term nuclear deal, a senior US official said Monday.

"It is our understanding that those talks will be in New York in mid-February, with dates still being confirmed on schedule, but it will be around that time period," State Department spokeswoman Jen Psaki said.

She confirmed that Iranian Foreign Minister Mohammad Javad Zarif and EU foreign policy chief Catherine Ashton had agreed to hold the next round of talks in the US metropolis, rather than in Geneva where the negotiations have been held so far.

New York has a similar UN "support infrastructure" to Geneva, Psaki said, which was "important for a comprehensive agreement."

She said it was not yet clear if the talks would be inside the UN headquarters in New York, adding that "this is the first step of the next stage here, and a lot of this is still being determined."

It also remained unclear whether any further talks would be held in New York, or whether they would move back to Geneva.

Under a landmark agreement between Iran and the world powers gathered as p5+1, which took effect January 20 and is to last six months, Tehran committed to limit its uranium enrichment to five percent, halting production of 20 percent-enriched uranium.

In return the European Union and the United States have eased crippling economic sanctions on Iran.

The negotiators have initially set out a six-month timeframe to negotiate a fully comprehensive deal, but it could be extended for a further six months.

Medium-enriched uranium is of particular concern to the international community since it can easily be purified to weapons-grade levels.

The West and Israel -- the region's sole, undeclared nuclear-armed power -- suspect Iran's nuclear ambitions include developing a military capability.

The allegations are repeatedly denied by Tehran, which says its atomic activities are entirely peaceful.

The Iranian news agency said earlier Monday that "negotiations between Iran and the P5+1 group on a definitive agreement will take place in New York at the end of Bahman," the Iranian month that ends on February 19.