Iran's state TV says Iran has warned that "illegitimate measures" could damage prospects of nuclear talks between Tehran and the west.
The report Thursday said Iran's top nuclear negotiator, Saeed Jalili, made the warning in a letter to Catherine Ashton, the European Union's foreign policy chief.
The letter is seen a reflection of Iran's concern about an EU ban on buying Iranian oil, set to go into effect July 1.
The West suspects that Iran intends to produce nuclear weapons. Iran insists its nuclear development program is peaceful. The five permanent Security Council members and Germany have had three rounds of talks with Iran on the issue.
In the letter, Jalili said the West should work on confidence-building steps instead of "illegitimate measures" that could harm the talks.