Russia has warned that proposed curbs on its banks' activities by the U.S. would be considered a "declaration of economic war" and that the country will retaliate, Reuters reported.
U.S. lawmakers have called for more Russian sanctions, which would directly affect Russian state-owned banks operating in the U.S. and would restrict their use of the dollar, Reuters noted.
"I can say one thing: If some ban on banks' operations or on their use of one or another currency follows, it would be possible to clearly call it a declaration of economic war," Prime Minister Dmitry Medvedev said during a trip to eastern Russia.
The U.S. recently said it will impose new sanctions on Russia over Moscow's alleged use of a nerve agent in an attempt to assassinate U.K. citizen and former Russian spy Sergei Skripal and his daughter in March. The sanctions will go into effect Aug. 22.
The curbs are already taking a toll, with the ruble's value falling by 6% over the course of a week.