BELGRADE, Serbia (AP) — Twenty years after NATO intervened to stop Serbia's onslaught in Kosovo, Belgrade is commemorating the victims of what it says was an aggression while Kosovo is hailing the beginning of its national liberation.

The staunchly opposed views of the two former war foes reflect persisting tensions over Kosovo, whose 2008 declaration of independence from Serbia is still not recognized by Serbia.

Serbian far-right supporters on Sunday burned NATO and European Union flags in Belgrade, condemning the 78-day bombing that ended Serbia's rule over the territory many here view as their nation's historic heartland.

Top Serbian officials are set to attend a main remembrance ceremony in a southern city later Sunday.

In Kosovo, leaders say NATO's air war brought freedom for their people.

More than 10,000 people died during the 1998-99 Kosovo war.