Fighting continued in several areas off Nagorno Karabakh on Friday, hours before talks were due to start in Washington.

Deadly clashes in the mountain region have seen over 5000 people killed in recent weeks, according to figures from Russian President Vladimir Putin.

The collapse of two Russian brokered ceasefires had also dimmed hopes of a quick end to fighting that broke out over Nagorno Karabakh, a breakaway territory which is within Azerbaijan but controlled by ethnic Armenians.

Pompeo will hold separate talks with the respective foreign ministers, although it's not clear if they'll meet each other directly.

Earlier this week, he said he hoped for a diplomatic solution on the right path forward could be found, with Putin expressing his desire for Washington toe act in unison with Russia.

However, the Armenian and Azeri leadership have both cast doubts on any peace arrangement being agreed anytime soon.