"Any arms supplies that continue, are on the rise, increase the risks of such a development," Russian Deputy Foreign Minister Sergei Ryabkov told the RIA Novosti news agency, in answer to a question about the possibility of a confrontation between Moscow and Washington.

On Tuesday, Washington said it will be supplying Ukraine with advanced missile systems, including the Himars multiple-launch rocket system that can simultaneously launch multiple precision-guided missiles.

Both Ukraine and Russia already operate multiple-launch rockets systems, but the Himars has superior range and precision.

The Himars system that Washington is providing to Ukraine will have a range of about 80 kilometres (50 miles).

According to Ryabkov, the US is determined to "wage war (on Moscow) to the last Ukrainian in order to inflict, as they say, a strategic defeat on Russia".

"This is unprecedented, this is dangerous," Ryabkov said.