"I don't believe the negotiations will remian fruitless," Rafsanjani, who is the leading candidate in next month's presidential election, told German ZDF television in Tehran.

"The negotiations are difficult and there is much scope for discussion," he added.

"The conclusion of discussions must lead to a solution, to see to it that the world is safer, in order that Iran only uses its nuclear technology for peaceful aims and that is possible," he said.

The comments follow crunch talks in Geneva on Wednesday between Iran and three leading European powers on Tehran's nuclear programme.

Afterwards, Iran's chief negotiator Hassan Rowhani said they believed an agreement could be reached "in a reasonably short time".