NEW YORK — U.S. Secretary of State Hillary Clinton welcomed Iran’s stated willingness to restart negotiations and called it an “important step.”

In comments to reporters after a meeting Friday at the State Department with Catherine Ashton, the European Union policy chief, Clinton said any resumption of negotiations with Iran would require sustained effort.

“We must be assured that if we make a decision to go forward, we see a sustained effort by Iran to come to the table to work until we have reached an outcome that has Iran coming back into compliance with their international obligations,” Clinton said. “We’re evaluating all of these factors. But I think it’s fair to say … that we think this is an important step and we welcome the letter.”

The letter in question was sent to Ashton on Tuesday by Iran’s chief nuclear negotiator, Saeed Jalili, which proposed new discussions between Iran and the West.

Tensions over Iran’s suspected nuclear weaspons program have been increasing steadily in recent weeks as increasing sanctions are imposed on the Islamic Republic and speculation persists of a possible Israeli military strike.