"We have announced before that any action to impose new sanctions means the death of the joint plan of action," she was quoted by the semiofficial Fars News Agency as saying Tuesday.
Iran agreed with members of the P5-plus-1 -- the United States, Russia, China, United Kingdom, and France, plus Germany -- to curtail some of its nuclear research activity in exchange for relief from some Western economic sanctions.
The Iranian government reacted angrily when U.S. lawmakers said they were considering more economic sanctions. The U.S. Treasury Department last week imposed sanctions on companies and individuals suspected of violating existing restrictions on Iran.
White House spokesman Jay Carney told reporters Monday the government would continue enforcing sanctions already on the books but was eager to move forward with the negotiating process.
Iranian Deputy Foreign Minister Abbas Araqchi said Washington's action undermined the spirit of the interim P5-plus-1 action plan, reached last month in Geneva, Switzerland. He said he was looking forward, however, to further talks.