MOSCOW — Russia's Foreign Ministry has harshly criticized new U.S. sanctions on Iran, calling them "undisguised blackmail" and warning that relations between Washington and Moscow will suffer if Russian companies are affected.

Congress on Aug. 1 slapped sanctions on Iran's energy, shipping, and financial industries as part of an effort to pressure Tehran over its suspected nuclear weapons program.

The new sanctions would hit foreign companies that mine uranium with Iran or help it export oil by providing tankers, insurance or banking services.

Foreign Ministry spokeswoman Maria Zakharova said Monday in a statement that while Russia supports U.N. sanctions, it opposes U.S. efforts to spread its legislation throughout the world and "rejects methods of undisguised blackmail used by the United States against the companies and banks of other countries."