U.S. Defense Secretary James Mattis give a news conference with Britain's Defence Secretary Michael Fallon (not shown) at Lancaster House in London March 31, 2017. Pool/Matt Dunham via Reuters LONDON (Reuters) - Iran is continuing to behave as an exporter of terrorism and still sponsors militant activity, U.S. Defense Secretary James Mattis said in London on Friday.

Asked about comments Mattis made in 2012 that the three primary threats the United States faced were "Iran, Iran, Iran," Mattis told reporters that Iran's behavior had not changed in the years since.

"At the time when I spoke about Iran I was a commander of US central command and that (Iran) was the primary exporter of terrorism, frankly, it was the primary state sponsor of terrorism and it continues that kind of behavior today," Mattis said.

(Reporting by Kylie MacLellan, William James and Phil Stewart, writing by Alistair Smout; editing by Stephen Addison)