Moscow/Brussels: Russia said on Thursday it was moving troops and military equipment from border regions near Ukraine, but NATO said a large "coercive force" remained in place.
Russia has previously failed to keep promises to move troops back from the frontier with eastern Ukraine, where pro-Russian separatists have declared independence.
Ukraine and its Western allies view them as a potential invasion force, given Moscow`s statements that it has the right to intervene in its former Soviet neighbour in order to protect Russian-speakers.
A NATO general said on Thursday that Russia was moving troops, though he said the size of the movement was unclear and that forces near the border remained a potential threat.
"The force that remains on the border is very large and it`s very capable and remains in a very coercive posture," U.S. Air Force General Philip Breedlove, NATO`s Supreme Allied Commander Europe, told a news conference.
NATO had previously put the number of Russian troops on the border at 40,000 but Breedlove said it was too early to classify their current size.
Russia`s defence ministry said on Thursday 15 transport planes and 20 trains carrying personnel and military equipment had been moved out of the Rostov, Belgorod and Bryansk provinces bordering Ukraine after completing military exercises there.
It did not say how many troops were being moved or how many were staying behind.
"The moving of units is continuing, having completed planned exercises testing military preparedness in field conditions, to loading stations," the Interfax news agency quoted a Defence Ministry statement as saying.
A withdrawal of forces from the border regions could ease tensions before Ukraine`s presidential election on Sunday, which the United States and EU hope will strengthen the embattled central government.
Kiev has accused Moscow of sowing disorder in its mostly Russian-speaking east where pro-Russian separatists have declared independence and asked to join Russia.
Russia denies destabilising its neighbour and has stopped short of endorsing the regions` independence or annexing the territories.