The Russian defense ministry said Wednesday it had chased off a Dutch submarine closely tracking its aircraft carrier in the Mediterranean as hundreds of thousands of NATO troops stand on "high alert" in Europe.

Russia said a number of NATO submarines had been following its fleet in the Eastern Mediterranean and that it drove away a Dutch submarine attempting "dangerous maneuvers" close to its positions. Russia's fleet is bound for Syria in order to support Syrian President Bashar al-Assad, who many NATO members actively oppose in the Syrian Civil War.

The incident came as NATO Secretary General Jens Stoltenberg indicated Monday he wanted to drastically reduce the response time of around 300,000 of the international military alliance's troops in deterring what he perceived as Russian aggression. Both Russia and NATO recently held military exercises near each other in the Balkans as tensions between the two powers escalate to their highest point since the Cold War.

“We have seen a more assertive Russia implementing a substantial military build-up over many years; tripling defense spending since 2000 in real terms; developing new military capabilities; exercising their forces and using military force against neighbors," Stoltenberg said.

“We have also seen Russia using propaganda in Europe among Nato allies and that is exactly the reason why Nato is responding. We are responding with the biggest reinforcement of our collective defense since the end of the Cold War,” he added.

It is a particularly uneasy time for NATO as its largest funder, the U.S., elected Donald Trump as president Wednesday. Trump has called the alliance "obsolete" and expressed his support for Russia in the past. He even suggested potential friendship between himself and Russian President Vladimir Putin. Current president Barack Obama's administration was considered a close NATO ally that attempted to push back against Russian foreign policy in Ukraine and Syria.