The head of the International Atomic Energy Agency (IAEA) has said the world is losing patience with Iran over its nuclear programme.
Mohamed ElBaradei (L) urged Iran to be transparent
Mohamed ElBaradei, who is in Oslo to receive the Nobel Peace Prize, said outstanding nuclear issues with Iran would be clarified next year.
The US and EU suspect Iran of pursuing nuclear weapons but Tehran says its programme is for civilian energy use.
The IAEA has repeatedly expressed concern about Tehran's activities.
Mr ElBaradei said European negotiators should continue talking to Iran.
"The parties need to sit together, discuss their grievances and reach a solution," he said.
"If we can do that without escalating the problem, all the much better."
The talks, with the UK, France and Germany, were suspended in August after Tehran restarted uranium conversion, a precursor to enrichment. No date has been set for their resumption.
The IAEA head urged Iran to be "as transparent as possible", adding that important pieces of its programme were still missing.
Mr ElBaradei, who shares the award with the IAEA, described it as a recognition of the agency's efforts to make the world a safer place.