The Kremlin said on Friday that the presence of U.S. paratroopers in Ukraine -- who are there to train local forces -- could “destabilize” the situation in the country. Three hundred U.S. paratroopers landed in Ukraine earlier this week for a six-month long training of Ukraine's national guard forces, who have been fighting pro-Russian rebels in the country's east.

"The participation of instructors or specialists from third countries on Ukrainian territory, where the domestic Ukrainian conflict is unresolved ... could destabilize the situation," Dmitry Peskov, a Kremlin spokesman, said, according to Reuters. Russia has previously claimed that American support for last year's nationwide protests, calling for the ouster of pro-Moscow leader Viktor Yanukovych, fueled the ongoing crisis in Ukraine.

The U.S. troops, belonging to the 173rd Airborne Brigade arrived in Yavoriv in western Ukraine to begin the training program, which is being called “Fearless Guardian,” and will be conducted for the newly formed national guard under the Contingency Security Fund. 

"We will be conducting classes on war-fighting functions, as well as training to sustain and increase the professionalism and proficiency of military staffs," Maj. Jose Mendez, a brigade operations officer, said in a statement, on Thursday.

The last training program involving the 173rd Brigade and Ukrainian forces took place in September last year, during the Rapid Trident series of exercises. Under the program, U.S. forces trained across Europe to promote “regional stability and security.”

"The 173rd is in a special position, as the only forwardly-positioned airborne brigade in Europe, we have the ability to be anywhere in the U.S. European Command area of responsibility in 18 hours or less," Mendez said, in the statement.

The latest training program comes amid escalating violence in eastern Ukraine, which has continued to engulf the region since Russia's annexation of Crimea last March. Since then, several regions in the eastern part of the country, including Donetsk and Luhansk, have demanded to secede from Ukraine. Several global powers, including the U.S. and the European Union, have slapped economic sanctions against Russia, accusing it of backing separatist groups in the region, and for sending its troops into eastern Ukraine.

Moscow has consistently denied its involvement in the regional conflict, and earlier this week, Russia conducted military drills with dozens of modern T-90A tanks in the Krasnodar region, south of its border with Ukraine, despite concerns voiced by Western powers, who have sought to strike a ceasefire deal between all the rival forces fighting in the region.