U.S. Secretary of State John Kerry says the world's major powers still want a diplomatic solution to the long-running dispute with Iran over its nuclear programme.<br/> <br />But Kerry warned on Sunday that talks could not drag on forever.<br/> <br />(SOUNDBITE) (English) U.S. SECRETARY OF STATE JOHN KERRY, SAYING:<br/> <br />"This is not something where you can play to the clock. You can't just delay and talk for the sake of talking."<br/> <br />His message came a day after talks between Iran and six other countries failed to break a deadlock.<br/> <br />Western powers suspect Iran is trying to develop nuclear weapons. Iran denies the accusation.<br/> <br />During a visit to Istanbul, Kerry said the onus was on Tehran to show its nuclear programme was for civilian purposes.<br/> <br />(SOUNDBITE) (English) U.S. SECRETARY OF STATE JOHN KERRY, SAYING:<br/> <br />"If you have a peaceful programme for nuclear power, as a number of nations do, it is not hard to prove to the world that it is peaceful."<br/> <br />Despite tensions bet
