The United States, France and Russia are calling on the leaders of Armenia and Azerbaijan to settle their long-running dispute over the Nagorno-Karabakh region of Azerbaijan.

The three countries that co-chair a committee of the Organization for Security and Cooperation in Europe (OSCE) said Friday they are committed to supporting Armenia and Azerbaijan as the countries finalize the details of a settlement.

Azerbaijani President Ilham Aliyev and his Armenian counterpart Serzh Sarkisyan will meet in Russia on July 17 to continue their negotiations.

But Nagorono-Karabakh's de facto leader, Bako Sahakyan, has also demanded a role in the talks. 

Speaking in Stepanakert Friday, Sahakyan said attempts to portray the disputed region as part of Azerbaijan are unacceptable.  He said the independence of Nagorno-Karabakh cannot be debated.

The Armenian-populated enclave of Nagorno-Karabakh declared independence from Azerbaijan in 1988, sparking a six-year armed conflict that claimed about 35,000 lives.  Firefights have periodically interrupted a cease-fire that went into effect in 1994.