NATO is preparing to hold its "biggest exercises in many years," reportedly the largest joint military drills since the end of the Cold War.

The Trident Juncture 2018 exercises are to " simulate NATO’s collective response to an armed attack against one ally."

The drills will come at a time of heightened tensions and just weeks after Russian and Chinese troops joined forces for Russia's largest exercise in decades.

NATO is gearing up for its "biggest exercises in many years," the alliance's Secretary General Jens Stoltenberg revealed Tuesday, according to multiple reports.

Around 45,000 troops will take part in the Trident Juncture exercises in Norway in late October and early November, the secretary said, according to AFP. The "fictitious but realistic" drills, reportedly the largest since the end of the Cold War, come on the heels of the massive Vostok 2018 joint military exercises involving tens, if not hundreds, of thousands of Russian and Chinese troops that were held in September.

In addition to troops, the 29 NATO allies and their partners will send 150 aircraft, 60 ships, and 10,000 vehicles to the training grounds.

The drills come amid heightened tensions with Russia. For instance, US Envoy to NATO Kay Bailey Hutchinson called Russia out Tuesday, accusing it of violating the 1987 Intermediate Nuclear Forces Treaty. Warning Russia that Moscow is "on notice," she said that the US might "take out the missiles" before they can be deployed if Russia refuses to change course.

Western allies have bolstered their military presence in the years following Russia's annexation of Crimea. Trident Juncture 2018 is designed to increase interoperability among allied and partner forces to respond quickly and effectively to an external threat, such as Russian aggression.

"It will simulate NATO’s collective response to an armed attack against one ally. And it will exercise our ability to reinforce our troops from Europe and across the Atlantic," Stoltenberg explained Tuesday. The aim is preparation for "large-scale military operations" under trying conditions, the Norwegian Armed Forces previously introduced, adding, "Exercises like this make NATO better prepared to counter any aggression, if necessary. "

In an effort to maintain transparency, NATO has invited Russia to monitor the joint military exercises. "All members of the Organisation for Security and Cooperation in Europe, including Russia, have been invited to send observers," the secretary said, according to Russian state media.

In early September, Russian and Chinese forces, along with a small contingent of Mongolian troops, trained together in eastern Russia, leading to significant speculation about stronger Russian-Chinese ties as both Moscow and Beijing confront Washington.

Russia touted the exercises as unprecedented, claiming that the drills included hundreds of thousands of troops and tens of thousands of tanks and other military vehicles. Many suspect that the joint exercises were actually much smaller than stated.