The negotiating group aiming at resolving the conflict in eastern Ukraine has ended its latest round of talks without firm results.

Martin Sajdik, the envoy from the Organization for Security and Cooperation in Europe, said Tuesday he hoped concrete agreements could be reached at the next round of talks in the Belarusian capital Minsk on July 21.

The so-called "contact group" includes the OSCE, Ukraine and Russia. Representatives from Ukraine's Russia-backed separatist regions are also included in the talks.

The negotiators are trying to implement a repeatedly violated cease-fire agreement that was reached in February. That agreement also called for the pullback of heavy weapons. Sajdik said discussions Tuesday included pulling back artillery of smaller caliber.

The United Nations estimates the war has claimed about 6,500 lives since April 2014.