A bitter territorial dispute between Armenia and Azerbaijan is eroding Russia’s ties with a traditional ally, a crisis that could strengthen the American relationship with an erstwhile Kremlin client and possibly increase friction between the United States and its wayward NATO partner,

The exodus began late Sunday, a trickle of vehicles that soon turned into an unceasing stream flowing along the mountain highway above Nagorno-Karabakh toward the Armenian border. By early Monday, almost a week after the Azerbaijani military took back Nagorno-Karabakh in a 24-hour blitz,

Armenia’s prime minister has called his country’s security relationships “ineffective,” in a swipe at Russia after Azerbaijan claimed the breakaway province of Nagorno-Karabakh following a swift military campaign.