Kazakhstan is conducting military drills simulating a response to a would-be separatist threat amid jitters over the Ukrainian crisis.

The Defense Ministry said Friday the three-day exercise was prompted by "geopolitical changes," but didn't elaborate. Under the scenario, Kazakh troops thwart an incursion by "extremists, terrorists and separatists" disguised as arriving refugees.

Governments in the region have long trumpeted concerns over possible spillovers of violence from Afghanistan.

However, the ministry's reference to a separatist danger seems to signal nervousness about Russia's annexation of Crimea and its support for the pro-Russian insurgency in Ukraine. Kazakhstan has a sizable ethnic Russian population and shares a long border with Russia.

Russia has successfully corralled several former Soviet states into the Eurasian Economic Union, including Kazakhstan, but some members are suspicious about Russia's intentions.