President Barack Obama has pledged that the United States and its allies would soon deliver a "significant regime of sanctions" against Iran for its nuclear program. At an ad hoc press briefing at the White House on Tuesday, Obama said a push for international sanctions against Iran was moving along fairly quickly and should be completed in the next few weeks. He stated that despite Tehran's denials it was clear to him that Iran was pursuing a path towards "nuclear weaponization" and “significant action” was necessary as a consequence. Obama said the international community was unified over what he called Iran's "misbehavior".

The US president’s bold remarks came after Iranian media reported that Tehran had begun the process of enriching uranium to 20-percent grade. Obama said he was pleased at Russia's quick disapproval of Iran's latest move, but added that it was still unclear how China – one of the five countries on the UN Security Council with veto powers – would respond to his initiative.

In London, British Foreign Secretary David Miliband said his Chinese counterpart had recently told him that Beijing was determined to stop Iran getting nuclear weapons. "It is very, very important that we therefore maintain maximum unity in developing the tactics to deliver on that goal," Miliband said.

Israel's Prime Minister Benjamin Netanyahu told European diplomats that "Iran is racing forward to produce nuclear weapons. This means not moderate sanctions, or watered-down sanctions. This means crippling sanctions, and these sanctions must be applied right now."

Nikolai Patrushev, secretary of Russia's Presidential Security Council: "The actions [Iran] is taking, including when it began enriching low-enriched uranium to 20 per cent, raise doubts in other countries, and those doubts are quite valid." He added: "Political-diplomatic methods are important for a resolution, but there is a limit to everything."

Meanwhile, the Brazilian government cautioned against new Iran sanctions. "We do not want Iran to have nuclear arms, let there be no doubt about that. They, like other countries, have the right to a peaceful [nuclear] program," Foreign Minister Celso Amorim told reporters in the capital Brasilia. "We want to reach certainty [on the nature of Iran’s nuclear program] through dialogue and peaceful means," he said. Brazil has lobbied for a permanent seat on the Security Council and hosted Iranian President Mahmoud Ahmadinejad in November 2009.