"Russia is the only country on earth that contains a nuclear capability that could destroy the United States," Gen. Milley told members of the Senate Armed Services Committee at a hearing to consider his nomination to serve as the next Army chief of staff, according to The Washington Times.
"It’s an existential threat to the United States, so it has capability. Intent, I don’t know; but the activity of Russia since 2008 has been very, very aggressive," he said.
Gen. Milley named other top threats as China, North Korea, the Islamic State and Iran, but did not place them in a specific order.
"My assessment today is that Russia poses the greatest threat to our national security," Marine Corps Gen. Joseph Dunford told members of the Senate Armed Services Committee earlier this month in a hearing to consider his nomination to be the next chairman of the Joint Chiefs.
"If you look at their behavior, it’s nothing short of alarming," he said.
Air Force Gen. Paul Selva, the nominee to serve as vice chairman of the Joint Chiefs, also put Russia at the top of his list of threats. He placed the Islamic State and other al Qaeda-inspired groups at the bottom of the list.
"Right now [the Islamic State] does not present a clear and presence threat to our homeland and to our nation," he said at his confirmation hearing earlier this month. "It is a threat we must deal with… but it does not threaten us at home."
Gen. Milley, in his confirmation hearing, said he would support providing defensive lethal aid to Ukraine.
Asked about the military’s ability to operate in Europe amid the growing Russian threat, Gen. Milley said he thought the U.S. military needed to increase ground forces on a temporary rotational basis to provide better deterrence.