Iranian media has said a US ScanEagle drone was captured "in the last few days" by the naval unit of the Islamic Revolutionary Guards Corps after entering Iranian airspace while gathering information over Gulf waters.
A US Navy spokesman said they were aware of the reports, and were looking into them.
Last month the US said Iranian warplanes shot at an American surveillance drone flying in international airspace. Iran said the aircraft had entered its airspace.
More top news
Novak Djokovic has secured his fifth Australian Open title with a four set 7-6 (7-5), 6-7 (4-7), 6-3, 6-0 victory over Andy Murray
Star of cult TV drama The Wire actor Idris Elba has said he sees himself as "an odd, tall black man that doesn't quite fit in".