(NewsNation) — A new military alliance appears to be brewing between Beijing and Moscow as Russia and China strengthen their military ties.

While a formal partnership between the two world powers isn’t in place yet, experts say this should spur the United States to plan new military strategies.

For years, the U.S. has been the military superpower of the world — but now, analysts say friendly ties between Russian President Vladimir Putin and Chinese President Xi Jinping could be the biggest threat the country has faced since the Cold War.

China has been providing Russia with economic support since Putin invaded Ukraine last February, and has been closely watching to see how that conflict plays out as a potential invasion of Taiwan looms.

Over the past few years, China’s militaries have participated in joint naval exercises with Russia, giving the country submarine technology that could threaten the U.S. Navy’s prominence.

Putin announced in November that Russia and China have also agreed to align on weapons development projects, further fueling their goal of becoming stronger than the American military.

Retired U.S. Army Major General William Enyart says it’s now clear that the goal from Xi and Putin is to take down U.S. military might.

“Any alliance between Russia and China would, in all likelihood, be relatively short term and would be a marriage of convenience,” Enyart said. “It’s not that they have any great interests in common other than a seen the U.S. deposed as the world’s only superpower.”

Experts now say the U.S. needs to urgently step up its military capacity, especially in Europe, while also strengthening its own alliances to offset the threats.