Iran's Supreme Leader Ayatollah Ali Khamenei speaks during Friday prayers in Tehran September 14, 2007. (File photo: VCG)

Iran's supreme leader Ayatollah Ali Khamenei said some US officials are "first-class idiots" in a speech on Wednesday. 

"Some US officials pretend that they are mad. Of course I don't agree with that, but they are first-class idiots," he said in the speech in Tehran, quoted on his official Twitter feed.