The United States on Tuesday hailed the resumption of talks between the presidents of Armenia and Azerbaijan, urging the two neighbors to seek a peaceful resolution of their decade-old territorial conflict over Nagorno Karabakh.

"The United States welcomes today's meeting between the presidents of Armenia and Azerbaijan in Vienna," State Department spokeswoman Jennifer Psaki said in a statement. "Their first meeting in almost two years, this summit is an important step toward restarting dialogue and demonstrates the leaders' shared commitment to bring an end to the Nagorno-Karabakh conflict."

Armenia and Azerbaijan have been locked in a bitter dispute over the mountainous region which was seized by Armenian-backed forces from Azerbaijan in 1991. A ceasefire was reached in 1994, and peace talks have been held ever since, with frequent exchanges of fire taking place across the frontline.

Armenian President Serzh Sargsyan and his Azerbaijani counterpart Ilham Aliyev on Tuesday held a closed-door meeting for about two hours in Vienna, Austria, to discuss the dispute.

The negotiation, mediated by the Minsk Group of the Organization for Security and Cooperation in Europe (OSCE), marked the first time the presidents have met in two years.

"As a co-chair of the OSCE Minsk Group along with Russia and France, the United States urges both presidents to work actively towards a peaceful resolution to the conflict, which has taken a heavy toll on the people on all sides," Psaki said.