Workers pour concrete at a site that will be used as a vehicle maintenance area at the Cincu military training facility in central Romania.
The images in this gallery were taken on September 20, and show NATO's work to massively expand the military training area near the Romanian village of Cincu as Russia's invasion of Ukraine grinds on.
An area of the Cincu site where lodging for NATO troops will be built by Belgian combat engineers.
In May this year, as NATO beefed up its presence across Eastern Europe, Colonel Vincent Minguet, the commander of the NATO Combat Group in Romania, announced the military alliance would be shifting its "center of gravity" from the Black Sea port city of Constanta, to Cincu, near the exact center of the country.
French soldiers take part in a NATO exercise at Cincu on September 20.
NATO say it currently has "over 40,000 troops, along with significant air and naval assets" under direct NATO command across the eastern edge of the alliance.
A lodging area for NATO troops at the Cincu facility
NATO says it's establishing four new "multinational battle groups" in Bulgaria, Hungary, Romania, and Slovakia.
French and Romanian soldiers walk next to an armored vehicle in the Cincu training grounds as the vehicle pops out smoke grenades on September 20.
The Cincu site has long been used for training by NATO troops, but the rebuilding that is under way will allow for some 1,000 NATO soldiers and heavy weaponry to be based at the facility.
A massive concrete area under construction at the Cincu training site.
According to Minguet, the base will allow "the creation of a permanent, stronger battalion, with more heavy weapons, to prevent any aggression or any destabilization in Romania." He added, "I think we will be here for a period of four-five years."
A Dutch sniper takes part in a training exercise at the Cincu training facility on September 20.
Minguet said regular drills at the site were "part of a message we are sending to the Russian Army."
Excavation under way at the Cincu site
Some locals have protested the large-scale construction near their village. In mid-September, a small bridge near Cincu had concrete blocks placed on it in an attempt to stop the heavy vehicles used by NATO. According to Romanian media, residents are worried the bridge is at risk of collapsing under the weight of vehicles far heavier than the bridge's 12-ton limit.
Dutch soldiers fire a dummy weapon during a NATO exercise at Cincu on September 20.
The relocation of the NATO battle group in Romania was scheduled to be done in June. It is unclear what has caused the delay in the move.
As part of what NATO calls a "fundamental shift in deterrence and defense," construction is under way in Cincu on a base that will house and train European troops.