Maintaining that a nuclear armed Iran is "intolerable" to the US as also to international community, a senior American official on Wednesday flayed Tehran's delaying tactics and accused it of never being sincere about negotiations on its controversial atomic programme.
Under Secretary of State for Arms Control and International Security Robert Joseph said the accent was on diplomacy but "options", meaning of the military, cannot be taken off the table.
Acknowledging the difficulties involved in sanctions he said US was confident that Russia and China will come around.
"Iran has been playing for time, and I would say quite successfully, for the last three years. We've seen this in the context of the process of moving this through the IAEA. We've seen it in the context of their insincere negotiations with the European 3," he told reporters at the Washington Foreign Press Centre.
"We've seen it now in the context of the Security Council resolution and I think we even see it today in the context of their postponement of the meeting between (European Union's Foreign Policy Chief Jaiver) Solana and (Iran's chief nuclear negotiator Ali) Larijani," Joseph said.
"We cannot allow Iran to have more time to pursue its nuclear programme. Part of its strategy has been to change the reality on the ground. We certainly saw this last April when they made their announcement that they had actually enriched uranium. We've seen it since in a number of different contexts," he said.