The official, speaking after Iran and six world powers agreed a framework for negotiations on the nuclear dispute in coming months, said on Thursday that Washington wants "companies to be mindful and thoughtful about what they're doing", when asked about Western firms interested in doing business now with Iran.

Most US and other sanctions on Iran remain in place after a limited easing that took place under an interim agreement reached between Iran and six world powers in November, the US official told reporters.

Iranian Foreign Minister Mohammad Javad Zarif said Thursday that Iran has reached an agreement with world powers on what would be discussed in the next round of nuclear talks which will be held on March 17th.

Zarif wrote on his Facebook page that he and EU foreign policy chief Catherine Ashton "agreed on the topics of discussion for the next round... as well as the expert-level (meeting)."

Iran and the six major world powers sealed an interim nuclear agreement in Geneva on November 24. Under the Geneva deal, the six world powers agreed to lift some of the existing sanctions against the Islamic Republic in exchange for Iran agreeing to limit certain aspects of its nuclear activities during a six-month period.

It was also agreed that no more sanctions would be imposed on Iran within this timeframe.

Iran has repeatedly announced that it is acquiring nuclear energy only for peaceful purposes and the International Atomic Energy Agency (IAEA) has confirmed that there is no diversion in Iran’s nuclear program.

NTJ/NJF