The United States is to begin training Ukrainian army troops in an expansion to its military involvement in the divided country, the State Department said Friday.

US troops have already deployed in small numbers to Ukraine to train National Guard forces, but under the new plan would also take on regular military units.

This will bring the total cost of a security assistance package for the embattled country -- locked in a conflict with pro-Russian separatists -- to $244 million since 2014.

But a spokesman said the training would take place in the west of the country, far from the frontline in the rebellious east and did not mark a major change in US strategy.

"This is going to be small unit training conducted by US Army Europe for Ukrainian Ministry of Defense personnel to help strengthen Ukraine's internal defense capabilities," Mark Toner told reporters.

"This training is part of our long-running defense cooperation with Ukraine and is taking place at the invitation of the Ukraine Government," he said.

"I don't have anything to announce in terms of any types of new equipment or new weaponry," he said. "Our focus is on... non-lethal aid. And there is no plans to change that."

Ukraine has waged a 15-month war against Russian-backed eastern insurgents, in a conflict that has claimed more than 6,500 lives.

The United States and its NATO allies have backed Ukraine diplomatically and have denounced what they see as Russia's intervention to support the rebels and prolong the destabilizing conflict.

But they have been cautious not to be drawn directly into military confrontation with Moscow, offering limited training support for Kiev's units rather than arms shipments.