Photos released on April 20 capture the massing of Russian military hardware on Ukraine's Crimean Peninsula and along the Russian-Ukrainian border.
Russian Sukhoi Su-34 military aircraft are lined up at Russia's Morozovsk Air Base.
The photos in this gallery were made between March 27 and April 16 by Maxar Technologies, a satellite-imaging company that provides "90 percent of the foundational geospatial intelligence used by the U.S. government."
Tanks, trucks, and other military equipment at the Pogorovo training area near Voronezh, Russia
The head of Maxar Technologies, Dan Jablonsky, told The Wall Street Journal his company was making the photos public because of "a commitment to transparency."
Tents and other equipment are collected at the Angarsky training area in Crimea during recent Russian military deployments to the area.
Tensions between the United States and Russia have soared in recent weeks and U.S. President Joe Biden announced new sanctions against Moscow last week over election interference and the SolarWinds cyberattack.
Airborne units are seen on maneuvers as the Russian military deploys at the Angarsky training area in the Crimea.
U.S. officials say the number of Russian troops in Crimea and near the Ukraine border has doubled in the past month.
The Kirovskoye Air Base in Crimea
Russian military planes at Saki Air Base in Crimea
Tanks and other military equipment on the Pogorovo training area near Voronezh, Russia
Russian military deployments at the Opuk training area on the Black Sea coast of Crimea
The Pogorovo military training area near Voronezh, Russia
On April 20, the Ukrainian military released its own images of tanks drilling at undisclosed locations in "eastern Ukraine."
Ukrainian tanks participate in drills at an undisclosed location in the eastern part of the country.
Ukrainian servicemen atop a Tunguska antiaircraft vehicle
A camouflaged Ukrainian tank takes part in drills.
On April 19, Ukrainian Foreign Minister Dmytro Kuleba called on the EU to "discourage Moscow from further escalation" by imposing further sanctions on Russia.