Satellite imagery taken this week shows military activity in multiple locations across Belarus, the annexed Crimea region of Ukraine and western Russia near Ukraine's border, a private U.S. company said on Friday.

U.S.-based Maxar Technologies, which has been tracking the buildup of Russian forces for weeks, said the images show recent helicopter deployments, consisting of both troop transport and ground attack helicopters, at multiple locations close to the border. They also show additional ground attack aircraft, air defense units and drone equipment have been deployed, it said.

Reuters could not independently verify what was shown in the images.

U.S. President Joe Biden said on Friday that Russian President Vladimir Putin has decided to invade Ukraine, and that he was spreading false information to try to build a pretext for a military strike that could happen in days. Russia says it has no such intention and accuses the West of irresponsible fear-mongering.

Maxar said the images showed that a large new deployment of at least 50 helicopters had arrived in northwest Belarus.

A new helicopter unit and battle group deployment consisting of tanks, armored personnel carriers and support equipment was deployed at an airfield about 16 kilometers (9.9 miles) from the Ukraine border, the satellite firm said.