Russia has warned the United States that there will be "unpredictable consequences" if Washington keeps arming Ukraine, The Washington Post reported on Friday.

"We call on the United States and its allies to stop the irresponsible militarization of Ukraine, which implies unpredictable consequences for regional and international security," The Post quoted Russia as saying in a diplomatic note to the United States.

U.S. President Joe Biden announced a new 800 million-dollar military aid package for Ukraine this week, including heavy equipment such as helicopters, howitzers and armored personnel carriers.