BELGRADE, Serbia (AP) — Officials say two Serbian soldiers have been killed in the explosion of an old NATO cluster bomb on Serbia's border with Kosovo.

The defense ministry says the officers died Wednesday while clearing a mine field near their barracks on Mount Kopaonik in southern Serbia that was left over from the 1999 war in Kosovo.

Hundreds of mine fields, including unexploded cluster bombs, were left in Serbia following NATO's 78-day bombing campaign that ended the war and stopped the crackdown by Serb forces on Kosovo Albanian separatists.

Kosovo declared independence from Serbia in 2008.