Russia has removed several thousand troops from within eastern Ukraine in what appears to be a positive step in the months-long Ukraine conflict.

NATO has reported that its seen a large-scale withdrawal of Russian forces from inside the border, but said that thousands of troops remain stationed on the Russian side, according to a Reuters report.

"There has been a significant pullback of Russian conventional forces from inside Ukraine, but many thousands are still deployed in the vicinity of the border," said Lt. Col. Jay Janzen.

"Some Russian troops remain inside Ukraine. It is difficult to determine the number, as pro-Russian separatists control several border crossings and troops are routinely moving back and forth across the border. Further, Russian special forces are operating in Ukraine, and they are difficult to detect," he said.

A NATO official on Sept. 4 said there were several thousand Russian troops in eastern Ukraine, but by last week NATO said that number had dropped to about 1,000. A ceasefire between Ukraine and pro-Russian rebels in the east began on Sept. 5.

Even after the ceasefire was in place, there was periodic shelling between the two sides. Janzen said those incidents have been decreasing recently.

"NATO welcomes these positive signs, and encourages all parties to continue to work towards a peaceful solution to this crisis," he said, adding that NATO is concerned about the large numbers of Russian forces deployed close to the eastern Ukraine border.

Despite the positive signs mentioned by Janzed, another NATO commander emphasized that the situation is far from resolved, The Wall Street Journal reported.

"The situation in Ukraine is not good right now," Gen. Phillip Breedlove said. "I think basically we have a cease fire in name only.

"The fluidity of movement of Russian forces and Russian-backed forces back and forth across that border makes it almost impossible to understand the numbers," he said.