A man watches Russian military jets performing in Alabino, outside Moscow, in August. The Russian military says major war games, the Zapad (West) 2017 maneuvers, set for next month will not threaten anyone. (Pavel Golovkin/AP)

Russia is readying this week for war games that Western security officials see as a muscular display of firepower along NATO’s most vulnerable region.

The exercises will show off a military that has been transformed under President Vladimir Putin into an effective force that has deployed to Syria and Ukraine in recent years. The official Thursday start — Western observers say the deployments started weeks ago — comes as relations with the West scrape all-time lows.

Moscow has insisted that the exercises will rehearse a strictly defensive scenario and will involve no more than 12,700 troops, just below the level that would require Russia to allow NATO observers under international agreements. The chief of the Russian general staff, Gen. Valery Gerasimov, said last week that the war games were “not aimed against any third country.”

But senior Western government officials believe the real number of Russian military personnel involved could reach 100,000 or more.

The Baltic countries that would be on the front lines of a Western conflict with Russia shrug off any direct threat, saying that the Kremlin has no reason to risk tangling with fresh NATO deployments this year that include significant U.S. reinforcements. But they also say that the week-long Zapad-2017 exercises are intended to unsettle their societies and send a political message that Russia is as credible — and dangerous — a military power as it was during the Cold War.

At NATO headquarters in Brussels, senior officials say their intelligence services are closely monitoring Russia as it draws up its military alongside their borders. They say that Moscow’s unwillingness to open the exercises to observation raises the risk of unplanned conflict stemming from misunderstandings.

“With more military activities along our borders in the air, at land and at sea, the risk for incidents, accidents, miscalculations is increasing,” NATO Secretary General Jens Stoltenberg said in an interview. “Transparency is the best way to avoid those kinds of incidents, accidents.”

Russia annually holds war games that rotate among the country’s military districts. This year’s installment involves the western forces, which account for Russia’s frontier from the Kola Peninsula high above the Arctic Circle all the way south to Ukraine.

Moscow has repeatedly stated that it is being open about the purpose and size of the war games, which simulate how to defend the northwest portion of Belarus from a domestic separatist insurrection fueled by support from abroad. Frants Klintsevich, a senior member of Russia’s upper house of parliament, said Western refusal to believe that shows that “the demonization of Russia continues.” 

But Western military officials say Russia has been hiding the true size and sweep of the war games, the official part of which will play out in Belarus, which borders NATO members Poland, Lithuania and Latvia.

They say that the drills with Belarusan troops are merely the tip of a major mobilization of Moscow’s upgraded and modernized military machine, with separate but coordinated maneuvers involving paratroopers, armored units, railroad troops, air and naval forces, strategic forces, security troops and units in the heavily armed exclave of Kaliningrad, home to Russia’s Baltic Sea fleet.

One element of the exercises may involve Russia’s 1st Guards Tank Army, a unit whose very existence is symbolic of the renewed tensions with the West. Russia in 2014 reconstituted the army — a formation whose ­Soviet-era purpose was to smash through NATO’s lines in the event of war — after disbanding it in 1998.

Despite the significance of the drills, Western officials interviewed last week dismissed the idea that the games are any more than that.

“We don’t see any imminent threat when it comes to any large-scale military operation against any European country now,” Stoltenberg said.

In Latvia, Foreign Minister ­Edgars Rinkevics said the country’s leaders are “not panicking” but are being “cautious” because “what we are seeing is that the exercises are of an offensive nature, they are exercising access and area denial, they are exercising against at least four NATO member states under the pretext that they are fighting [separatists.]”

Viewed from the Baltic nations, the exercises reflect Putin’s oft-repeated stance that Russia is surrounded by a hostile and aggressive force in NATO, and they have two apparent goals.

One is to rehearse the capability to seal off Lithuania, Latvia and Estonia, and deny access to the Baltic Sea to NATO forces attempting to come to their rescue. The other is to present a strategic challenge to U.S. and NATO leaders by demonstrating the high cost of defending the Baltics, thus sowing uncertainty about the viability of the alliance.

“We in Estonia already live in constant fear. This is the predominant feeling in society, fear. If society feels threatened, you can manipulate it,” said Dmitri Teperik, chief executive at the International Center for Defense and Security in Tallinn, Estonia.

Confidence in NATO took a hit in the Baltics after the election of President Trump, who repeatedly characterized the alliance as “obsolete.”

But the arrival early this year of four multinational NATO battalions, one for each Baltic state and Poland, helped ease worries, as did repeated visits from Trump deputies who are more clearly committed to the alliance than the president is. During the ­Zapad exercises, an additional company of U.S. forces will be present in each Baltic country, a presence that is symbolically important, Teperik said. 

“The flag tells Russia that if you have a problem with Poland or Lithuania, you have to take it up with Washington,” he said. “The campaign rhetoric was worrisome, but actions have proven that America as a state and as a society was committed to the alliance.”

The Baltic countries, as with NATO as a whole, have learned their lessons since 2014, when Russia shocked the world with its lightning-fast annexation of Ukraine’s Crimean Peninsula using “little green men,” troops in uniforms without insignia, said Janis Garisons, state secretary of Latvia’s Defense Ministry.

He said Moscow might use the exercises to try out new cyberattacks or wrinkles in information warfare.

“They’ve been very successful in deceiving us. Hybrid warfare is not about green men with a lack of insignia. It is about giving us doubts,” Garisons said. “Russian information war wants to convince our population that our country is small and indefensible, and that NATO won’t defend us.”

Ambassadors from NATO’s 29 member countries will meet repeatedly in the coming days for updates about the exercises. And the alliance’s No. 2 military commander is going to spend this week crisscrossing the Baltics and Poland as the Russian activities get underway.

Military planners say they will be watching carefully to understand Russia’s capabilities and its concerns. NATO forces have kept watch over preparations for the exercises, but they have not raised major concerns, the senior commander of the U.S. Air Force in Europe said.

“We have kept close tabs on those activities,” Air Force Gen. Tod Wolters told reporters in a briefing. “There is nothing extraordinary or out-of-the-ordinary as we have witnessed up to this point, but again, we will continue to remain smart and vigilant.”

Birnbaum reported from Brussels.