US soldiers had to take the city at night and find and neutralize the enemy headquarters. Opposing them were the 45th unit of Latvia's National Guard.
The National Guard had fortified themselves with barbed wire and sand bags.
Commander Andris Rieksts said it was a new experience for his unit.
"There's equipment from Ādaži [military base] here as well. I think that for many this'll be the first time they'll see such equipment in action. To me it is a great opportunity to show my National Guard the dynamics of warfare in a close-to-real-life setting," he said.
A total of 30 National Guard defended the city against 120 US troops, with both sides using pellets filled with color.
Observer Joshua Lawrence said both sides did their task well.
"Observing these exercises is a great experience. As the previous group did the task well, we did not change the strategy," he said.
The exercises took three days with a different US company partaking each night.
The above video (Latvian) gives an idea of the surroundings and the equipment used.