With the Pentagon’s top expert saying that Russia is ready to use nuclear weapons, both Russia and China are threats to the international order and U.S. global dominance, according to U.S. Secretary of Defense Ash Carter.

Russia, China Threaten Global Order: U.S. Defense Secretary

Carter said that Russia poses a great threat to the world order with its military invasions in Eastern Europe, including Ukraine and the Baltic states, and Russian President Vladimir Putin’s alarming actions with his country’s nuclear weapons.

Speaking to the Reagan National Defense Forum in California, Carter added that the U.S. defense establishment is actively seeking ways to deter Russian aggression and protect U.S. allies. He noted that China’s expanding influence and increasing military might also pose great challenges to U.S. global dominance, saying that both Russia and China are conducting “challenging activities” at sea, in the air, in space, and in cyberspace.

“Most disturbing, Moscow’s nuclear saber-rattling raises questions about Russian leaders’ commitment to strategic stability, their respect for norms against the use of nuclear weapons, and whether they respect the profound caution nuclear-age leaders showed with regard to the brandishing of nuclear weapons,” Carter said.

Political and military experts noted that Carter’s remarks were perhaps the strongest he has ever expressed about the United States’ former Cold War enemy. However, Carter said that the White House does not seek a “cold, let alone a hot, war” with Russia, nor does it. seek to make Russia an enemy.

“But make no mistake; the United States will defend our interests, our allies, the principled international order, and the positive future it affords us all,” he said.

Carter’s comments come amid Russia’s ongoing military operation in Syria, in which it bombs U.S.-backed rebels and ISIS militants, while China makes confident steps at asserting its dominance outside of its borders.

U.S. risks nuclear war with China and Russia

With the ongoing hot conflict between Washington and Beijing over the disputed islands in the South China Sea, there is a high possibility of a military confrontation in the region, according to the authors of an op-ed published in The Age last week. Hugh White and Michael J. Cole argued that “the harsh reality” is that by supporting Taiwan against Chinese claims on its sovereignty, the U.S. risks unleashing a nuclear war against China.

“U.S. leaders might have to ask themselves whether they are willing to risk a nuclear attack on the continental US in order to defend Taiwan from China. If the answer is no, then Taiwan’s status quo might become harder and harder to sustain,” the authors wrote.

And with Vladimir Putin recently ordering his security council to develop defensive nuclear equipment, the Pentagon says the Kremlin is poised to use nuclear weapons to “bring a speedy peace,” as reported by ValueWalk on Friday. But a war involving the world’s two largest nuclear powers – Washington and Moscow – would “probably spell, if not the end of humanity, the end of any possibility of a comfortable future for humanity,” as reported by ValueWalk, citing Press TV’s interview with Don DeBar, U.S. political analyst.

Despite the deadly consequences, a nuclear war with China and Russia is “our likely future,” according to a Reagan-administration official. Dr. Paul Craig Roberts, the former U.S. assistant secretary of the Treasury for economic policy, warned that Russia and China will never accept U.S. hegemony, which will likely bring more conflicts and confrontations between the two sides, including a nuclear war. Roberts also wrote earlier this year in his blog that China is “confronted with the Pivot to Asia and the construction of new U.S. naval and air bases to ensure Washington’s control of the South China Sea, now defined as an area of “American National Interest.”

ISIS, Russia and China threaten the global order: Carter

Carter referred to several pillars of the global order that he believes must be protected and strengthened: respect for state sovereignty, freedom from coercion, peaceful resolution of disputes and freedom of navigation, all of which have been violated by China and Russia to some extent.

“Some actors appear intent on eroding these principles and undercutting the international order that helps enforce them,” he said. “Terror elements like ISIL, of course, stand entirely opposed to our values. But other challenges are more complicated, and given their size and capabilities, potentially more damaging.”

He stated that neither Russia nor China can “overturn” that order, but both “present different challenges” for it. As for Russia’s military operations in the Middle East, Carter accused Putin of escalating the situation.

“In Europe, Russia has been violating sovereignty in Ukraine and Georgia and actively trying to intimidate the Baltic states,” he said. “Meanwhile, in Syria, Russia is throwing gasoline on an already dangerous fire, prolonging a civil war that fuels the very extremism Russia claims to oppose.”

Carter promises more U.S. patrols, China ready to respond militarily

As for China, Carter promised more U.S. sea patrols in the South China Sea to demonstrate freedom of navigation. Two weeks ago, an American guided-missile destroyer, the USS Lassen, came within China’s 12-nautical-mile zone around the Spratly archipelago. The incident sparked outrage among the Chinese, with China’s Foreign Ministry issuing a statement in which it warned that the nation will defend its sovereignty, security and rights in the maritime space. And the Chinese side is “ready to give an appropriate response to any country’s provocations,” according to the statement. The United States’ decision to send additional patrols to the disputed area raises concerns about whether Beijing will be as restrained as it was two weeks ago or whether it will be prepared to respond militarily.

“As a rising power, it’s to be expected that China will have growing ambitions and a modernizing military,” Carter said. “But how China behaves will be the true test of its commitment to peace and security.”

He also added that Washington is shifting its focus toward the Asia-Pacific region with plans to deploy its best naval and other military equipment and ships to the area which China has large influence over.

“We are also changing fundamentally our operational plans and approaches to deter aggression, fulfill our statutory obligations to Taiwan, defend allies, and prepare for a wider range of contingencies in the region than we have traditionally,” Carter said.