A senior negotiator for Iran played down the prospect of reaching an agreement with world powers on Thursday on its controversial nuclear programme, Iranian media reported. "I do not think the negotiations will reach a conclusion tonight," Abbas Araqchi, a deputy foreign minister, was quoted as saying by the Mehr news agency after an afternoon session with the so-called P5+1 group of world powers. But he added that the talks had been "serious" and had focused on remaining "points of difference."