Russia is bolstering its military presence on its western border, sending tens of thousands of soldiers to newly built installations within easy striking distance of Ukraine.

The moves, which come as Moscow ratchets up confrontation over the Black Sea peninsula of Crimea, are a centerpiece of a new military strategy the Kremlin says is meant to counter perceived threats from the North Atlantic Treaty Organization (NATO).

Military analysts say the deployments appear to be an effort to build a more permanent and robust military posture around Ukraine, where Russia has carried out covert military interventions aimed at maintaining influence in its West-leaning neighbor.

“Russia’s plans around the Ukrainian border show a real intent to use force if needed,” said Anton Lavrov, a defense analyst at Moscow-based think tank CAST. “They would be Russia’s first line of assistance if the pro-Russian rebels in east Ukraine needed help.”

The Russian Defense Ministry didn’t respond to emailed questions.

U.S. military officials, having closely monitored Russian movements of troops and equipment in the two years since Moscow’s seizure of Crimea, said they haven’t detected signs of an immediate threat. Any shift in Russian military posture reflects broader plans, a senior military official said Thursday.

“It’s a long-term trend; there is nothing new,” the official said.

Some U.S.-based analysts in recent weeks have pointed to Russian plans to reorient forces in various spots to potential areas of conflict, adding the shifts don’t necessarily indicate imminent military activity.

Click for more from The Wall Street Journal.