U.S. threatens Iran with unprecedented sanctions

The United States is getting ready to hit Iran with new, tougher sanctions, with one top official saying Tehran now faces an "unprecedented" degree of isolation, The Voice of America reports.

U.S. officials, speaking on the condition of anonymity late Friday, said the sanctions could be unveiled as early as Monday and would target Iran's petrochemical industry.  They said the new sanctions would seek to stop foreign companies from investing in ventures like oil refineries.  

U.S. national security adviser Tom Donilon said Saturday that Iran is finding itself more isolated than ever before.  

Donilon spoke to reporters while traveling with U.S. President Barack Obama in Indonesia.  The national security adviser also said that like the U.S., China and Russia want to make sure Iran does not develop nuclear weapons.

On Friday, both China and Russia sought to ease the tone of a resolution by the United Nations' nuclear watchdog that was critical of Tehran.  The final wording cited "deep and increasing concern" over Iran's nuclear activities but stopped short of referring Iran to the U.N. Security Council or setting a deadline for the country to comply with the International Atomic Energy Agency's requests for additional information.