CAPU MIDIA, Romania (AP) — U.S. and French troops that are part of a NATO battlegroup in Romania will hold a military exercise on Thursday to test the 30-nation alliance’s eastern flank defenses, as Russia’s full-scale invasion of neighboring Ukraine nears its one-year anniversary.

The joint combat drills at the Black Sea training range in Capu Midia, dubbed Eagle Royal 23, will involve some 350 multinational battlegroup troops who will practice firing live ammunition.

Romania’s defense ministry said that the goal of the drills — held between Feb. 2 to Feb. 10. — is to test NATO’s “interoperability of artillery systems” in a fictitious Article 5 collective defense scenario on the alliance's southeastern territory.

NATO’s Article 5 is central to its founding treaty. The clause requires every alliance member to come to the assistance of any ally that requests it. Article 5 has been invoked only once: by the U.S. in the wake of the Sept. 11 terrorist attacks in 2001.

In response to Russia’s invasion of Ukraine last February, NATO bolstered its presence on Europe’s eastern flank, including by sending additional multinational battlegroups to alliance members Romania, Hungary, Bulgaria, and Slovakia.

Late last month, around 600 French soldiers deployed to Romania also held live combat exercises to test NATO's readiness in the region. That drill took place at a training range near Romania’s eastern town of Smardan and involved some 200 military vehicles, including four French Leclerc battle tanks.

In January, NATO deployed surveillance planes to Romania, from where they will fly missions for several weeks to monitor Russian military activity near the alliance's borders.

Follow the AP’s coverage of the war at https://apnews.com/hub/russia-ukraine