Isthmus of Perekop
On the same day, more troops in unmarked uniforms, assisted this time by what appeared to be local "Berkut" riot police (as well as Russian troops from the 31st Separate Airborne Assault Brigade dressed in Berkut uniforms), established security checkpoints on the Isthmus of Perekop and the Chonhar Peninsula, which separate Crimea from the Ukrainian mainland. Within hours, Ukraine had effectively been cut off from Crimea.