U.S. Army engineers will construct miles of roads and several training facilities across six Eastern European NATO nations by September, a report released Monday says. The attempts to improve military infrastructure are part of continuing U.S. efforts to reaffirm support for Eastern European allies amid increased Russian aggression in the region.

Starting in May, the U.S. engineers and contractors began work on improved roads, tank trails and new training facilities in the Baltic states of Latvia, Estonia and Lithuania, as well as Poland, Bulgaria and Romania, the Army Times reported. The United States has set aside some $70 million to fund the construction efforts as part of the Obama administration’s European Reassurance Initiative, a $1 billion plan to demonstrate the country’s commitment to NATO allies wary of Russia’s activity.

New roads and tank trails would facilitate the movement of NATO troops throughout the six nations as the alliance prepares to ramp up training and military maneuvers throughout the region. NATO has built up its military presence in Eastern Europe as a check against Russia, which annexed the formerly Ukrainian territory of Crimea in March 2014 and purportedly supported pro-Moscow separatist rebels active in Eastern Ukraine.

Under the European Reassurance Initiative, the United States increased its contribution to NATO’s naval forces in Eastern Europe, dispatched U.S. military officials to lead training exercises and increased the “rotational presence” of U.S. troops in the region, the White House said in a 2014 news release. Aside from an increase in NATO military exercises, the Pentagon announced last month it would send about 250 pieces of heavy weaponry to Eastern European nations. Separately, NATO expanded its rapid reaction force earlier this year to consist of 30,000 troops, citing the threat posed by Russia’s activity.

Russia has also stepped up military exercises and expenditure as Russian President Vladimir Putin vowed to overhaul the country’s armed forces by 2020. Last month, a top Russian official warned the Baltic states would make themselves “targets” if they agreed to house U.S. military equipment.