Fighting erupted Sunday between Armenia and Azerbaijan, two former Soviet republics that have clashed over control of a disputed territory for three decades, raising fear of a new full-blown war in the South Caucasus.
Armenia declared martial law and military mobilization after accusing Azerbaijan of launching a missile and artillery attack on the breakaway region of Nagorno-Karabakh. Azerbaijan blamed Armenia for triggering the fighting, calling it an act of aggression. Both sides reported civilian deaths and injuries, without providing details.
Hostilities over the volatile province, a mountainous region that is inside Azerbaijan but run by ethnic Armenians, have flared in recent months, with skirmishes in July killing at least 16 people. A six-year war in the 1990s claimed some 30,000 lives and displaced hundreds of thousands of people.
Since a 1994 cease-fire, Nagorno-Karabakh—which is about the size of the U.S. state of Delaware—remains heavily militarized. The latest escalation in the long-running conflict risks drawing in regional powers Russia and Turkey and leading to large civilian casualties.
Ankara has thrown its weight behind Azerbaijan, raising concerns that the standoff in the disputed province could evolve into another proxy fight between Turkey and Russia, which are on opposite sides of military conflicts in Syria and Libya.