I am deeply concerned by the outbreak of hostilities in Nagorno-Karabakh and call for urgent de-escalation, restoring the ceasefire, and a resumption of negotiations between Armenia and Azerbaijan. The United States should be pushing for more observers along the ceasefire line and calling for Russia to stop cynically providing arms to both sides, while reviewing our own security assistance programs to ensure no military capabilities are being repurposed for offensive means. The Trump administration also needs to step up its diplomatic efforts, together with fellow OSCE Minsk Group co-chairs France and Russia, to seek a peaceful resolution and to support confidence-building measures. The eruption of hostilities in Nagorno-Karabakh runs the risk of escalating into a larger regional conflict, which is why third parties in the region must stay out of this conflict and the Minsk Group mediators must immediately seek de-escalation and a return to negotiations.
Joseph R. Biden, Jr., Statement by Vice President Joe Biden on Hostilities in Nagorno-Karabakh Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/345097