NATO’s large-scale military exercise, “Saber Guardian 2017,” has started in Bulgaria, with participation of 25,000 soldiers from 20 countries, including Serbia.

The Beta agency reported this on Tuesday, citing a Defense Ministry announcement that said 79 Serbian soldiers would participate in the July 7-22 drills taking place in Hungary, Romania, and Bulgaria.

According to AP, the goal of the exercise, led by US Army Europe, is to “increase the interoperability of participating countries and demonstrate resolve and readiness to act in support of security and stability in the Black Sea region.”

These drills have been held each year in the Black Sea region since 2013.