Iran's Foreign Ministry says allegations that the president-elect took part in the 1979 Tehran hostage crisis are part of a smear campaign.
A foreign ministry spokesman Sunday warned Europeans not to fall into what he called "the trap of the Zionist media."
Members of the European Union are negotiating with Iran to stop its nuclear enrichment activities.
President-elect Mahmoud Ahmadinejad has denied any involvement in the seizure of the American embassy in Tehran. But several former hostages say they recognize Mr. Ahmadinejad as one of the hostage-takers.
The White House says it is looking into the allegations.
Some information for this report provided by Reuters and AP.