Washington is hosting this week the foreign ministers of the two South Caucasus rivals. Tensions between them have flared anew after Azerbaijan installed a road checkpoint at the start of the Lachin Corridor, the only route linking Armenia to the disputed Nagorno-Karabakh territory.
"The two sides have discussed some very tough issues over the last few days, and they've made tangible progress on a durable peace agreement," Blinken said at a closing session for the bilateral peace negotiation.
He added that he believes that there is an agreement within sight and that Washington will continue to help both countries cross the finish line.
Karabakh is internationally recognised as part of Azerbaijan, but home to mostly ethnic Armenians. Azerbaijan committed to keeping the route open as part of a Russian-brokered ceasefire in 2020 that ended a six-week war between the two countries.
Azerbaijan said it had established the checkpoint in response to what it said were Armenian weapon supplies to Nagorno-Karabakh. Yerevan denies that charge.
The Kremlin on Tuesday said any efforts to resolve the conflict between Armenia and Azerbaijan were welcome, but that the basis of any long-term solution should be the 2020 Russian-brokered peace agreement.
The stand-off is seen as a test of Russia's resolve to mediate disputes in the region. Armenia - formally an ally of Russia through a mutual self-defense pact – has repeatedly called on Moscow to use its peacekeeping force to stop what it calls Azerbaijan's "gross violation" of the peace deal.
The parties have agreed to hold talks in Moscow at some point in the future, though no date has been set yet.
Despite years of attempted mediation between them, Armenia and Azerbaijan have yet to reach a peace agreement that would settle outstanding issues such as the demarcation of borders and return of prisoners.
(Reuters)