Iranian Foreign Ministry spokesman Ramin Mehmanparast was quoted by the semiofficial Fars News Agency as saying Tehran didn't feel the time was right for direct talks with U.S. officials.
"We are not witnessing a behavior from the American side that shows to us they are really regretful and want to ... have a respectful behavior toward Iran from now on," he said.
"Whenever such signals are sent, we will be definitely ready for talks with all countries in a bid to materialize our national interests."
The New York Times, in an October report citing unnamed White House officials, reported that an "in principle" agreement was reached to discuss the nuclear issue one-on-one with the Iranians after the Nov. 6 election in the United States.
U.S. President Barack Obama said after his re-election this month that reports of imminent talks weren't true, however.
Tehran this week lashed out at the U.S. government for canceling a Helsinki meeting in December to discuss a Middle East free of weapons of mass destruction. Iran, for its part, is accused of seeking nuclear weapons capabilities, an allegation it denies.