WASHINGTON (Reuters) - United States President Barack Obama's chief of staff said on Sunday the election of Iranian President Hassan Rohani was a "potentially hopeful sign", and that if he lived up to his obligation "to come clean on this illicit nuclear programme, he will find a partner in us."

Speaking on CBS' Face the Nation television show, Mr Denis McDonough said: "If he (Rohani) is interested in, as he has said in his campaign, mending Iran's relations with the rest of the world, there is an opportunity to do that."