WASHINGTON — The US military's plans to send troops into Romania and Bulgaria as a deterrence to Russian aggression could expand to include Hungary, the Czech Republic and Russia's southern neighbor, Georgia, according to a US Army official spearheading the effort.

Exercises between US troops with Poland, Estonia, Latvia, Lithuania, which began last April, will expand through the summer, said Col. Michael Foster, of the 173rd Airborne Brigade, based in Vincenza, Italy. The exercises are part of the US Army Europe-led land force assurance training mission, known as Operation Atlantic Resolve — now expanded into "north" and "south" components.

"So by the end of the summer, you could very well see an operation that stretches from the Baltics all the way down to the Black Sea," Foster said, speaking at the Center for Strategic and International Studies here on Monday. "As you connect countries, there is almost a line of US troops."

The 173rd this week will also be sending nearly a battalion's worth of soldiers to the Ukraine to train troops from its national guard, considered separate from Atlantic Resolve, Foster said, "but certainly tied into deterring Russian aggression."

At the request of Ukrainian officials, the training will focus on the gamut of small-unit skills, from first aid to basic ambush operations, aimed at limiting the advantage of Russian forces, Foster said. Through October, three US Army company units will be paired with three Ukrainian elements who have been fighting Russian-backed separatists in eastern Ukraine.

"What we have been asked to do, and the issue that exists in the fight, is not an issue of teaching the Ukrainians things they don't know but refining their processes and pushing them forward," Foster said. "The fight from my perspective only is it's not an imbalance of capability, its an imbalance of capacity in some paces, or a refinement in one area that's giving Russia tactical overmatch in a few specific areas."

Those units would be overseen by a battalion headquarters, the 4th Infantry Division's tactical command post, which has control of Atlantic Resolve. In the event of a crisis, the host nations would be in charge

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"We have had some great discussions about, 'What do we do in case of Russian aggression, in case of kinetic, lethal activity in the vicinity of our soldiers,' " he said. "I think we've got a good plan in place."

The European-brokered ceasefire deal signed in the Belarussian capital Minsk on Feb. 12 calls for tanks and artillery to be withdrawn from a buffer zone of between 50 and 140 kilometers (around 30 to 90 miles). Though both sides say the process is underway, The Organization for Security and Cooperation in Europe (OSCE), which is tasked with monitoring the ceasefire, said Monday it was "not yet in a position to provide verification of withdrawals," AFP reported.

In April, paratroopers from the 173rd will jump into Romania and Bulgaria. They will be replaced by about 1,000 soldiers from the 2nd Cavalry Regiment and 1st Brigade Combat Team, 3rd Infantry Division, according to a report in Army Times.

Operation Atlantic Resolve will continue in Estonia, Latvia, Lithuania and Poland with about 900 soldiers from 1st BCT, 3rd Infantry, who are rotating in from Fort Stewart, Georgia, as part of the Army's regionally aligned forces concept.

On Tuesday, the U.S. Army that 450 soldiers from 4th Battalion, 3rd Aviation Regiment, 3rd Combat Aviation Brigade from Hunter Army Airfield, Georgia, will deploy to the Ansbach, Germany area by mid-March, for a nine-month deployment.