"Iran and the European Union began their political and commercial negotiations based on mutual respect, and just as Iran did not accept preconditions to start the talks, it will very certainly not accept preconditions to continue them," foreign ministry spokesman Hamid Reza Asefi said.
The EU, which unlike the United States advocates a policy of constructive engagement with the Islamic republic, has been conducting trade talks with Iran over the past year.
But Brussels has made an agreement dependent on progress on Tehran's record on human rights, terror, peace in the Middle East and nuclear inspections.
The Iranian foreign ministry said Italy, the current holder of the rotating EU presidency, had warned Iran that unless there was rapid progress on the nuclear issue, the talks on hammering out a trade and cooperation agreement would effectively stop.
Last Friday, the International Atomic Energy Agency (IAEA) gave Iran until October 31 to clear up widespread suspicions it is using an atomic energy programme as a cover for nuclear weapons development.
The resolution, passed by the IAEA's board of governors after intensive US lobbying, demands Iran answer all the IAEA's questions regarding its enrichment activities, provide unrestricted access to IAEA inspectors and provide a detailed list of its nuclear-related imports.
One of the IAEA's demands is that Iran sign an additional protocol to the nuclear Non-Proliferation Treaty, which would allow inspectors to make surprise visits to suspect sites.