There’s quite a bit going on between Ukraine and Russia, and as a result, Korn has released a statement regarding their decision to stay away from that area (for now):
As The State Department of United States of America has recently issued a travel advisory warning against any non-essential travel to Kiev, both Korn and the promoter have decided it would be in the best interest of the fans that the show scheduled for May 16, 2014 be postponed to a later date. Full ticket refunds will be available immediately from point of purchase. All of Korn’s other dates on their tour of Russia will continue as planned.