Serbia is holding large military drills to mark 100 years since the end of World War I in an apparent show of force amid rising tensions with Kosovo.
The live-ammunition maneuvers on Saturday, dubbed "The Century of Winners," include 8,000 soldiers, 100 battle tanks and MiG-29 fighter jets supplied by Russia.
Tensions recently have increased in the region, with Serbia and Kosovo accusing each other of undermining efforts at reconciliation following a 1998-99 war which ended after NATO intervention.
The former Serbian province declared independence in 2008 which Belgrade doesn't recognise.
Serbia is often wrongly accused of starting World War I after a Serb nationalist assassinated the Austrian archduke in Sarajevo, Bosnia, in 1914. Serbia suffered the worst losses proportional to the size of its army during the war.