He said, however, that the Armenian and Azerbaijani governments will have to show political courage to reach a final deal. He said Washington views the next couple of months as a "real window of opportunity" to resolve the dispute.
Yerevan and Baku have been formally at war since 1988, when the predominantly ethnic Armenian enclave of Nagorno-Karabakh seceded from Soviet Azerbaijan.
The United States, Russia, and France co-chair the Minsk Group of nations mandated by the Organization for Security and Cooperation in Europe to mediate between Armenia and Azerbaijan.
The Nagorno-Karabakh Conflict
Click on the image to view an enlarged map of the Nagorno-Karabakh conflict zone
In February 1988, the local assembly in Stepanakert, the local capital of the Azerbaijani region of NAGORNO-KARABAKH, passed a resolution calling for unification of the predominantly ethnic-Armenian region with Armenia. There were reports of violence against local Azeris, followed by attacks against Armenians in the Azerbaijani city of Sumgait. In 1991-92, Azerbaijani forces launched an offensive against separatist forces in Nagorno-Karabakh, but the Armenians counterattacked and by 1993-94 had seized almost all of the region, as well as vast areas around it. About 600,000 Azeris were displaced and as many as 25,000 people were killed before a Russian-brokered cease-fire was imposed in May 1994.
CHRONOLOGY: For an annotated timeline of the fighting around Nagorno-Karabakh in 1988-94 and the long search for a permanent settlement to the conflict, click here.Click on the icon to view images of the Nagorno-Karabakh conflict (Flash required)
To view an archive of all of RFE/RL's coverage of Nagorno-Karabakh, click here.