A total of 1,300 troops from 15 nations, either active NATO members or would-be members, have come together for a military exercise in western Ukraine – even as the fragile truce in the east of the country barely holds.

The exercise, code-named “Rapid Trident” has been an annual event since 2006, and has been organized by the Germany-based US European Command (EUCOM). It was initially planned to have this year’s drills in mid-July, but they were postponed because of heavy fighting in eastern Ukraine.