Iran should come clean on its nuclear programme: Obama

Putting Iran on notice, President Barack Obama today said it must "come clean" on its nuclear programme at October one talks with P5 Plus1 countries and that the international community is united in its opposition to Tehran's atomic programme.

The US President also warned that he had not ruled out any option, including military action, to deal with Tehran's nuclear programme, but said his preferred course of action is to resolve this in a diplomatic fashion.

"I think Iran is on notice that, when we meet with them on October 1, they are going to have to come clean and they are going to have to make a choice," Obama told a press conference flanked by his French counterpart Nicolas Sarkozy and British Premier Gordon Brown at the end of the G20 Summit.

Obama's statement comes hours after the existence of a second uranium enrichment facility in Iran came to light and a week before a rare meeting between Iran and the five permanent United Nations Security Council members, plus Germany in Geneva on October 1.

"With respect to the military, I've always said that we do not rule out any  options when it comes to US security interests. But I will also re-emphasize that my preferred course of action is to resolve this in a diplomatic fashion. It's up to the Iranians to respond," Obama said.

The President also said he had seen an "unprecedented show of unity" at the United Nations General Assembly in New York and the G20 summit in confronting Iran on the nuclear programme issue.

Earlier at the start of the G-20 Summit, Obama said the US, Britain and France presented  "detailed evidence" to the IAEA on Thursday showing that Iran "has been building a covert uranium enrichment facility near Qom for several years."

The three countries also demanded an immediate investigation into the facility and threatened a stiff response if Iran fails to conform to international obligations regarding nuclear development.

"Iran's decision to build yet another nuclear facility without notifying the IAEA represents a direct challenge to the basic compact at the center of the nonproliferation regime," Obama said.

"The size and configuration of this facility is inconsistent with a peaceful program," he said. The three countries also served an ultimatum to Iran to fulfil its international obligations on its newly-detected uranium enrichment facility by December or face stringent sanctions.