You're reading: New York Times: Putin drills ground troops at Ukraine’s doorstep as US warns against intervention

 MOSCOW — President Vladimir V. Putin ordered a surprise exercise of ground and air forces on Ukraine’s doorstep Wednesday, intending to demonstrate his country’s military preparedness at a time of heightened tensions with Europe and the United States over the turmoil gripping Russia’s western neighbor. The Obama administration said any Russian military intervention in Ukraine would be a costly and “grave mistake.”

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