President Obama
President Obama Reuters

Russia harshly criticized new U.S. sanctions against Iran on Monday, calling them “overt blackmail” and a "crude contradiction of international law," warning that relations between Washington and Moscow could significantly sour if Russian companies are affected.

President Barack Obama signed into law new sanctions on Iran’s energy, shipping and financial industries on Friday that would harm foreign companies that mine uranium with Iran or help the regime export oil by providing tankers, insurance or banking services.

"We are talking about restrictive measures not only against Iran but also affecting foreign companies and individuals working with it, including in the hydrocarbon extraction and transport, petrochemicals, finance and insurance industries," the Russian Foreign Ministry said in a statement.

"We consider efforts to ... impose internal American legislation on the entire world completely unacceptable," it said. "We reject methods of overt blackmail that the United States resorts to in relation to the companies and banks of other countries."

"Those in Washington should take into account that our bilateral relations will suffer seriously if Russian operators ... come under the effects of the American restrictions."

Russia reiterated its stance that unilateral sanctions, as opposed to those approved by the Security Council, are counterproductive, arguing that the "constant increase of pressure on Tehran" undermines unity among the six nations leading diplomatic efforts to rein in Iran's nuclear program and impairs the chances of success, Rueters repoted.

Talks between Iran and the six powers in Moscow in June failed to yield desired results over Tehran's nuclear activities including the enrichment of uranium which Western nations fear is part of a bid for weapons capability.