The aid Washington currently supplies to Ukraine is limited to non-lethal items, such as first aid kits and body armor.
In January, the leader of the self-proclaimed Donetsk People's Republic (DPR) Alexander Zakharchenko told reporters that independence fighters had found US-made weapons on the territory of the Donetsk airport after the Ukrainian military pulled out of the area.
The Russian Foreign Ministry has emphasized that the United States would breach the Geneva agreements on the Ukrainian settlement, reached by Russia, the European Union, the United States and Ukraine on April 17, 2014, if it supplied lethal weapons to Kiev.
The military confrontation between Kiev forces and independence supporters in eastern Ukraine began in April 2014 and recently intensified despite a ceasefire agreement reached in September last year.
More than 5,000 people in Ukraine have died in the conflict, according to the United Nations.