Speaking before the Senate Armed Services Committee on Thursday, Dunford noted that Russia's "behavior" is "nothing short of alarming," adding that Moscow "presents the greatest threat to our national security."
Referring to mythical Russian involvement in the civil war in eastern Ukraine, which Moscow has repeatedly dismissed for lack of evidence, Dunford stated it would be "reasonable" to provide Ukraine with lethal weaponry.
"Chairman, from a military perspective I think it's reasonable that we provide that support to the Ukrainians," Dunford noted. "Frankly, without that kind of support, they are not going to be able to defend themselves against Russian aggression," the general added.
The general's comment was met with enthusiastic approval from Republican Senator John McCain, the committee's chairman, who took the opportunity to score some political points against Barack Obama by declaring that while "Vladimir Putin's Russia continues its onslaught in Ukraine," the US "has refused Ukraine the weapons it needs and deserves for its defense."
The hearing also covered other military matters, including the war in Afghanistan, the air campaign against ISIL, US assistance for rebels fighting against the Syrian government, and issues related to future defense budgets.
On Wednesday, The Wall Street Journal reported that Washington and Kiev are presently in negotiations on the expansion of the US military training program in western Ukraine to include regular army and special forces units.