The US President's Chief of Staff, Denis McDonough, has said that the election of Hassan Rouhani to the Iranian presidency is a "potentially hopeful sign".
He added that Rouhani "will find a partner in us" if he lives up to his nation's obligation to "come clean" on its nuclear programme.
More top news
Police investigating the disappearance of a British toddler in Germany more than 35 years ago have released an image of a suspect.
Lord Stevens said drones should be prohibited near sensitive sites like airports.
The strike action was due to begin on Wednesday.