Britain, France and Germany have said they want Iran to halt uranium processing at its Isfahan plant which Tehran resumed in August.
Otherwise, the EU trio say, they will back US efforts to haul Iran before the UN Security Council, where it could eventually face sanctions. Iran says its nuclear programme will only be used to generate electricity, not make bombs.
"We are ready to continue unconditional talks and hope to reach a result through talks and avoid the Council," Foreign Ministry spokesman Hamid Reza Asefi told a news conference on Sunday.
Breakdown in talks
Almost two years of talks between Iran and the EU broke down in August when Tehran broke UN seals at the Isfahan plant where uranium is converted into a gas that can be used to make nuclear reactor fuel or bomb warheads.
"Iran will never again suspend Isfahan facility's activities. It was a voluntary measure and was lifted automatically," Asefi said.
Washington and the EU are trying to persuade the governing board of the International Atomic Energy Agency (IAEA) to send Iran to the Security Council in November for violating international nuclear obligations.
Asefi says Iran will not suspend
work at the Isfahan plant
US Secretary of State Condoleezza Rice failed on Saturday to win Russia's support for referring Iran to the Council, but said Washington still expects to be able to refer Tehran to the Council "at a time of our choosing" if diplomatic efforts fail.
Rice flew to Moscow on a surprise trip on Saturday to press President Vladimir Putin to commit to backing a referral if Iran continues to defy the West, diplomats said.
But with Russia leery of punitive measures against a country it has strong commercial ties with, Putin was unmoved and reaffirmed Russia's position that the IAEA must deal with Iran.
Rice acknowledged Putin did not change his mind and she settled for accepting Moscow's pledge to work on coaxing Iran back to the talks with the EU over curbing its programmes.
Asefi accused the United States of upping the pressure on IAEA board members to refer Iran to the council.
"America and Rice are pressuring other countries to vote against Iran, but we hope those countries act independently," he said.
"The council cannot be used as a Sword of Damocles against Iran. We cannot be threatened by referral."