Updated

Officials say that at least four soldiers have been killed in a border skirmish between Armenian and Azerbaijani troops.

Armenian Defense Ministry spokesman Artsrun Ovanissian three Armenian servicemen died in fighting Thursday. Azerbaijan's Defense Ministry said one of its troops was killed in combat.

Armenia and Azerbaijan blamed each other for the fighting.

The two ex-Soviet nations have been locked in conflict over Nagorno-Karabakh.

Nagorno-Karabakh is officially part of Azerbaijan, but since a separatist war ended in 1994 it has been under the control of forces that claim to be local ethnic Armenians but that Azerbaijan claims include regular Armenian military. Efforts to negotiate a settlement have failed and sporadic clashes have continued.

An outbreak of fighting in April killed about 75 soldiers from the two sides.