"American weapons can lead to new victims in our neighboring country and we cannot remain indifferent to this", Ryabkov said, according to a foreign ministry statement. "In fact, [this decision] supports Kiev's "party of war", that is the political forces, which are for use of force in settlement of the Donbass problem".
"U.S. assistance is entirely defensive in nature, and as we have always said, Ukraine is a sovereign country and has a right to defend itself", the department said in a statement. John McCain said heavy-weapon support from the U.S.is "years overdue".
This is another development from the USA that Russian Federation was expected to criticize. Russian Federation may take the issue of lethal weapon sales to Ukraine to the UN Security Council, the Deputy Chairman of the State Duma's Defense Committee, Yuri Schvytkin said.
Mr. Poroshenko said in his Facebook post that he had confirmed the weapons deal with Secretary of State Rex W. Tillerson, calling it "a trans-Atlantic vaccination against the Russian virus of aggression".
The statement also said that "Tillerson emphasized that the United States would further support Ukraine". The state department pointed out that approving the "commercial export" of lethal arms was "nothing new", because Washington has repeatedly allowed U.S. arms manufacturers to sell weapons to Kiev "under the previous two administrations".
On Wednesday, the Trump administration had announced it was allowing the export of some small arms to Ukraine.
The State Department is also poised to sign off on the sale of "enhanced defensive capabilities" that officials say could include American Javelin anti-tank weapons systems.
ABC News said previously President Trump was expected to endorse a plan envisioning supplies of antitank equipment worth $ 47 million to the Ukrainian authorities.
"Vladimir Putin has chosen war instead of peace in Ukraine".
Russian Foreign Ministry spokeswoman Maria Zakharova responded to reports that the USA and Canada have chose to allow weapons exports to Ukraine by accusing Washington and Ottawa of making false claims about the conflict in Ukraine as a "pretext to begin large-scale lethal weapons deliveries to Ukraine".
The announcement of the arms shipment comes as US diplomats are negotiating a United Nations peacekeeping force for eastern Ukraine. The decision is likely to inflame tensions with the Kremlin.