File Photo: Members of Iran's Revolutionary Guards march during a military parade in Tehran September 22, 2007 (Photo: Reuters)
Iran said the United States would be "joining the terrorists' camp" if it chose to designate its Revolutionary Guards a terrorist organisation.
"The world should be thankful to the Revolutionary Guards for its fight against terrorists, especially against Daesh (Islamic State)," Iranian government spokesman Mohammad Baqer Nobakht said in a weekly news conference broadcast live on state television.
"So by taking a stance against the Revolutionary Guards and designating it a terrorist group, the Americans would be joining the terrorists' camp," he added.
President Donald Trump is expected to designate Iran's most powerful security force, the Islamic Revolutionary Guards Corp (IRGC), as a terrorist organisation, as he rolls out a broader, more hawkish U.S. strategy on Iran next week.