 Russia is concentrating its army in the Arctic region this time. Russia has continued expanding its military bases in the Arctic region despite significant losses in its war on Ukraine, according to a new series of satellite images obtained by CNN. NATO Secretary General Jen Stoltenberg also said there is now a significant Russian military build-up in the high north, with recent tensions causing the alliance to double its presence in response. The findings also come as a senior Western intelligence official said that Russia has withdrawn as much as three-quarters of its land forces from the high north region near the Arctic, sending them to bolster its faltering invasion of its neighbor, Ukraine. The satellite pictures show a series of Russian radar bases and runways undergoing improvements over the past year. The images do not show dramatic development, but rather the continued progress of fortifying and expanding an area analysts say is of vital importance to Russia's defense strategy at a time of great strain on Moscow's resources. According to Maxar, the images demonstrate continued work on the radar stations at the Olenegorsk site on the Kola Peninsula in northwest Russia and at Vorkuta, just north of the Arctic Circle. They also appear to show work moving ahead to complete one of five Resonans and radar systems at Ostrovodnoi, a site located by the Barents Sea near Norway and Finland in Russia's west. The Resonans-N are claimed by Russian officials to be able to detect stealth aircraft and objects. Three new radomes, the weather-proof enclosures used to protect radar antennas, were completed this year at the Tixi Air Defense site. In the far northeast, according to Maxar's images and analysis, there are also improvements to a runway and parking apron at Nogorskoye Air Base, Russia's northernmost military facility, and runway improvement at Tempe Air Base on Koltanee Island in the northeast of the country.