The Obama administration imposed new sanctions Wednesday on Iran’s Revolutionary Guard in its bid to hurt Iran’s nuclear programme. The force is said to be main force  that is propelling Iran into nuclear league.

The US Treasury has designated a Revolutionary Guard commander and four subsidiaries of a construction firm owned or controlled by the elite unit as “proliferators of weapons of mass destruction and their supporters.”, State Department spokesman Philip Crowley said  in Washington.

The Revolutionary Guard was subjected to US sanctions in the past also and those sanctions were targetted at its other business interests.

The United States has been consulting with Russia, China, Britain, France and Germany on Iran, but Beijing wants a negotiated solution and now appears to be the lone hold-out against sanctions.

Iran announced on Tuesday that it had begun work to enrich uranium to 20 percent for a medical research reactor in Tehran.