The U.S. Army in Europe is pressing ahead with the deployment of nearly 300 soldiers to Ukraine to train local national guard troops there despite the ongoing conflict between Ukrainian government forces and Russian separatists, a defense official said.

The training mission originally was scheduled for March, but was delayed and given high-level scrutiny amid concerns that it could inflame tensions with Russia. U.S. military officials have condemned Russia for invading the Crimea region last year and arming the separatists in eastern Ukraine.

"It was undergoing some reviews, so it got off to a late start," Army Col. Steve Warren, a Pentagon spokesman, said Thursday.

The mission will send 290 soldiers from the 173rd Airborne Brigade, based in Vicenza, Italy, to a training center in Yavoriv, near Ukraine's western border with Poland, several hundred miles away from the fighting between Ukrainian forces and separatists.

The training mission likely will begin in late April and continue into fall, defense officials said.

Many U.S. military officials have said Russian military aggression in the region over the past year is intended in large part to fray the alliance between the U.S. and its European allies in NATO.