On Saturday Russian President Vladimir Putin ordered about 17,600 Russian troops to return to their bases from Rostov. The region in Russia borders east Ukraine, where pro-Russian insurgents have been battling government troops since April.
"We would welcome withdrawal of troops on that border, and we are anxiously watching what is happening," U.S. Air Force Gen. Philip Breedlove, the Supreme Allied Commander Europe, told The Associated Press on the sidelines of a NATO conference in the northern Greek city of Thessaloniki.
"We have not seen major movements yet," he said. "Now we will watch to see if there is delivery on the promise."
Russia has consistently denied Ukrainian and Western claims that it has supported the insurgency in eastern Ukraine with weapons, expertise and fighters, saying troops stationed in Rostov are participating in drills.
NATO has countered previous Russian claims of troop withdrawals. In the spring, the U.S. and NATO said Russia had deployed about 40,000 troops near the border, though Putin ordered the troops back to their home bases in late May. While the U.S. and NATO did confirm those moves, in August they said Moscow was again bolstering its forces in the region and that Russia had allowed troops and vehicles to cross the border to assist the separatists.
"Actions speak louder than words," another top NATO military commander, Gen. Frank Gorenc, who heads the alliance's air command and the U.S. Air Forces in Europe, told the AP. "And the fact of the matter is, in today's environment strategic messaging without action are just words. And so their actions remain to be seen."
Breedlove noted it was important for the West to comprehend the possible motives for Russia's actions in Ukraine.
"We have to understand in the West that Mr. Putin may actually have felt threatened along the lines of Ukraine leaning to the West, both in the European union and in the NATO alliance," Breedlove said.
Putin has repeatedly accused the U.S., the EU and NATO of stonewalling Moscow's economic and security concerns and trying to pull Ukraine into the Western orbit. He accused the West of encouraging the ouster of Ukraine's former president in February, and cast the annexation of Crimea the following month as a necessary move to protect Russian speakers there.
Breedlove also said he thinks Putin wants to maintain its influence in the eastern part of Ukraine as it is of economic importance to Russia.
Before the crisis erupted, Russia and Ukraine had maintained close economic ties. In particular, Russian industrial plants, including many arms makers, have relied on Ukrainian-built components. Ukraine has provided Russia with helicopter engines, air-to-air missiles, navy turbines and many other items. Some of nuclear-tipped intercontinental ballistic missiles in the Russian inventory were built in Ukraine during the Soviet times, and the Russian military has relied on Ukrainian expertise in maintaining them.
Breedlove wouldn't speculate about whether Russia posed a threat.
"Let's just look at capability and capacity. There is still a very, very large force and a very, very capable force sitting on the border of Ukraine," he said. "And so rather than guess about intentions, let's just point out that Mr. Putin maintains on that border the capability to go into Eastern Ukraine should he choose to."
Vladimir Isachenkov in Moscow contributed to this report.