BELGRADE, Serbia (AP) — The Serbian foreign minister says U.S. and Russian envoys have met in Belgrade in an effort to end the conflict in eastern Ukraine.

Minister Ivica Dacic said Kurt Volker and Vladislav Surkov held talks Saturday in the Serbian capital “dedicated to the Ukrainian crisis.” No details have emerged from the closed-door meeting.

Volker tweeted the meeting is to discuss “how to catalyze Minsk implementation and restore Ukraine’s territorial integrity.”

A 2015 peace deal signed in the Belarusian capital of Minsk called for a cease-fire between the Russian-backed separatists fighting Ukrainian forces in eastern Ukraine, a conflict that has left over 10,000 dead, but the deal was often violated.

Volker had refused to meet with Surkov in Russia and Surkov is barred from the European Union under sanctions for Russia’s role in Ukraine.