Russia’s beefing up its air and missile defense systems near its borders with NATO countries, according to local media reports.

This week, Sputnik reported that Russia’s Western Military District is increasing the number of S-400 Triumf and Pantsir-S air defense systems in its area of operations.

"Modern S-400 Triumf long-range air defense systems and Pantsir-S gun-missile air defense systems will be put in service with air defense units of the Western Military District by the end of this year," Col. Oleg Kochetkov, a spokesperson for the Western Military District, said, Sputnik reported.

The S-400 is Russia’s most advanced air and missile defense system, and its deployment in greater numbers along Russia’s borders with NATO could challenge the latter’s ability to achieve air dominance in the event of a conflict with Moscow.

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As Robert Farley has explained on The National Interest, “An S-400 battery has three kinds of missiles, each intended to engage aerial targets at different ranges. The longest ranged SAM can engage at 400km, with shorter-ranged missiles compensating with enhanced capabilities for killing fast, maneuverable targets. The S-400 can also engage ballistic missiles.”

Farley went on the write: “The sensor systems of the S-400 are thought to be extremely effective, especially as Russia can layer S-400 defense zones in nearly every conceivable theater of conflict. Positioning the S-400 at Kaliningrad could endanger NATO air operations deep into Europe.”

“At least in the early days of the war,” Farley warned, “the S-400 and its associated systems could neutralize NATO airpower, undermining one of the central pillars of the Western way of war.”

The Pantsir-S gun-missile, on the other hand, is geared towards combating more short-range threats. Global Security, a defense website specializing in technology, has noted that the Patsir-S system, “combines two 30mm anti-aircraft guns and 12 surface-to-air missiles, and can simultaneously engage two separate targets, ranging from aircraft to missiles to guided bombs."

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The Sputnik report did not specify how many additional S-400 or Pantsir-S systems will be deployed in the Western Military District, nor did it say exactly where the systems would be placed.

The move to beef up its air and missile defense along the border region comes as the West and Russia engage in a game of tit-for-tat escalations.

Earlier this month, the New York Times reported that the United States is placing heavy weaponry along Russia’s borders in Eastern Europe. “The Pentagon is poised to store battle tanks, infantry fighting vehicles and other heavy weapons for as many as 5,000 American troops in several Baltic and Eastern European countries,” the report said .

At a NATO meeting this week, the organization announced it was tripling the size of its rapid reaction force to 40,000 troops, and there has also been talk about revising NATO’s nuclear doctrine. Meanwhile, Russian President Vladimir Putin said that Moscow would introduce 40 new intercontinental ballistic missiles into the military this year.

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Both the United States and Russia have indicated recently that they are planning for a prolonged rift between their countries. Ashton Carter, the U.S. defense secretary, said Washington is planning on the current rift with Moscow outlasting Putin’s tenure as Russian president. Moscow quickly followed up with similar statements.

That being said, Putin did call President Barack Obama on Thursday, and the two leaders chatted on the phone about a host of different issues.

Zachary Keck is managing editor of The National Interest. You can find him on Twitter: @ZacharyKeck .