Finnish, Swedish, American and Ukrainian troops are among those taking part in a large-scale, Nato-led military drill beginning on Monday in Estonia.
Nearly 16,000 troops from 11 countries will participate in what is set to be the largest military exercise ever held in Estonia.
The drill, codenamed "Hedgehog 2022", will involve all branches of the armed forces, and consist of air, sea, land and cyber training exercises.
Russia's invasion of Ukraine did not trigger the drill, as it was scheduled years ago, according to Deputy Commander Veiko-Vello Palm of the Estonian Defence Forces.
He, however, said many countries signed up for the exercise at the last minute.
Some 250 members of the Finnish military are set to take part in the exercises, with the objective to develop and test the capabilities of the jaeger company and the combat engineer company on international missions.
"We participate in Hedgehog from our own point of departure, and the coming exercise entity both strengthens our international interoperability and strongly supports the needs of our national defence," said Lieutenant Colonel Risto Kohonen of the Finnish Defence Forces.
In addition to Estonian troops, nearly 4,000 soldiers from ten countries will participate, with Finland, Sweden, Ukraine and Georgia the only non-Nato members to take part.