The Associated Press reported Defense Secretary Ash Carter saying that Russia is "going back in time" with their confrontational attitude and "nuclear saber-rattling."
"Moscow's nuclear saber-rattling raises troubling questions about Russia's leaders' commitment to strategic stability, their respect for norms against the use of nuclear weapons, and whether they respect the profound caution that nuclear-age leaders showed with regard to brandishing nuclear weapons," he said.
He said Russia's "loose talk" about using nuclear weapons is concerning. It shows that there is a "war-like" attitude in their foreign policy.
Carter explained that in the past 25 years the United States has not had to prepare a deterrence for Russia. He further explained the ways the Obama administration is preparing the United States and its allies.
"These include plans to add a third U.S. Army combat brigade in Europe in the coming year as part of a $3.4 billion initiative designed to further reassure allies of the U.S. commitment to their security and to deter Russian aggression."
Carter cited examples of Russia's recent hostile actions, which included the annexation of Crimea in 2014 and Russia's seeming aggression and intimidation tactics toward the Baltic states. Since the Baltic states are in NATO, the United States has a legal obligation to protect them if Russia acts on this.
"We do not seek to make Russia an enemy. But make no mistake, we will defend our allies, the rules-based international order, and the positive future it affords us," he said.
Carter expressed his desire to increase relations with Russia. He cited how his career started in the Cold War era trying to keep the peace between Russia and the United States. He said he hoped to continue these relations without Russia's confrontational approach.
"The United States will continue to hold out the possibility that Russia will assume the role of a constructive partner moving forward, not isolated and going backward in time as it appears to be today," he said. "Much of the progress we've made together since the end of the Cold War, we accomplished with Russia. Let me repeat that. Not in spite of Russia, not against Russia, not without Russia, but with it."