The US diplomat said Thursday Iran seem to keeping its ambitious nuclear program in progress as Iran denied a request from leading countries to abandon its nuclear enrichment program.

"Iran must not be permitted to develop the capacity to build or deliver a nuclear weapon," said Nicholas Burns, undersecretary of state for political affairs. In his speech to the Senate Foreign Relations Committee he said that the US should seek ways to deny Iran’s nuclear ambitions as the country violated the 2004 agreement that suspends nuclear activities.

The UN also suggested to punish Iran and referred the country to the International Atomic Energy Agency, the U.N. nuclear watchdog agency.

"We have not been, over the past 25 years, against communication. But the Iranian government has pretty consistently refused to have any interest in wanting to have a responsible discourse," Burns said.

Iranian national security adviser Hassan Rowhani is to meet with foreign ministers from Britain, France and Germany these days to discuss the issue.