"These US actions directly contradict the agreements reached in Minsk on February 12, signed by Kiev officials and supported, as far as we are concerned, by Washington," Foreign Ministry's spokesman Alexander Lukashevich said in a statement.
"It could be viewed as a first step toward supplying Ukraine with advanced US weaponry, which Kiev's 'party of war' desires so much."
Washington's support of Ukrainian war hawks could lead to a new bloodshed in a country sharing border with Russia, the Russian Foreign Ministry's spokesman said.
In December 2014, the US Congress passed and US President Barack Obama signed into law the Ukraine Freedom Support Act, which allows lethally arming the conflict-torn country.
Russia called the legislation provocative, warning that such an approach could escalate violence in the country. The United States has so far refrained from providing Ukraine with lethal weapons.