Russia just upped the ante for the missile defense world by unveiling a new arsenal of nuclear weapons, although it did not come as a surprise to the United States – and the Pentagon urged calm over the developments.

"We are not surprised by these statements, and the American people should rest assured that we are fully prepared," chief Pentagon spokeswoman Dana White told reporters Thursday.

During a two-hour state-of-the-nation speech on Thursday, President Vladimir Putin announced an arsenal of nuclear weapons that will significantly boost the Kremlin's military capabilities. The weapons include a nuclear-powered cruise missile, a nuclear-powered underwater drone and a new hypersonic missile.

"They didn't sneak up on us," Thomas Karako, director of the Missile Defense Project at the Center for Strategic and International Studies, told CNBC. "This is kind of the state of play for the missile threat and missile defense challenge of the day.

"Congress has already highlighted the Russia threat, and — guess what — Vladimir Putin today is confirming the rightness of that diagnosis," Karako added.

Still, Karako said, the weapons Putin described, less than three weeks before he is expected to claim re-election, render NATO's mostly U.S.-led missile defense systems useless.

"Unfortunately, we are kind of behind the curve in terms of our cruise missile defense capabilities," Karako said. "This is why — I'm a broken record on this — this is why we have to open the aperture and look at the full spectrum of missile threat challenge. It's not just about ballistic missiles anymore."

White, the Pentagon spokeswoman, said the Defense Department was prepared for developments like these.

"Our stance has never been, they know very well that it's not about them, our missile defense has never been about them," White said. "We need to ensure we have a credible nuclear deterrent and we are confident and are prepared to defend the nation no matter what."

Putin's speech cited other nations' actions as a key factor in supercharging Russia's arsenal.

"I want to tell all those who have fueled the arms race over the last 15 years, sought to win unilateral advantages over Russia, introduced unlawful sanctions aimed to contain our country's development: All what you wanted to impede with your policies have already happened," Putin said. "You have failed to contain Russia."

In an effort to back his bellicose rhetoric, Putin spoke in front of a projection showing video clips of the new weapon platforms.