The US Energy Department said it conducted a "subcritical" test at an underground site in Nevada on Wednesday to study the behaviour of nuclear materials without triggering an atomic explosion. It was its first since February last year.
Iranian foreign ministry spokesman Ramin Mehmanparast "condemned the recent US nuclear test," saying it displayed "inattention to full disarmament which is a deep-seated demand of international public opinion."
Iran "as one of the victims of weapons of mass destruction (during its 1980-88 war with Saddam Hussein's Iraq), will pursue the supreme leader's fatwa regarding the prohibition of production, storage or use of such weapons until it has been fully realised," Mehmanparast added.
He was referring to a 2005 religious decree by Ayatollah Ali Khamenei in which he declared the atomic bomb to be against the principles of Islam.
Washington and other Western governments have expressed scepticism about Iran's position and suspect that it is trying to develop a weapons capability under cover of its civil nuclear programme.
Tehran insists the programme is exclusively for power generation and medical purposes.