OHCHR's spokeswoman warned that the real number could be higher.
"From 6,000 to 10,000 civilians have been killed in Donbass since the military operation began," the Donetsk People's Republic (DPR) parliament speaker Andrei Purgin said.
In February, the leaders of Russia, Ukraine, France and Germany worked out a new ceasefire deal for Ukraine. However, both sides report regular violations of the truce.
The participants of the latest contact group meeting on May 6 formed four working subgroups on key aspects of the de-escalation of the conflict. The subgroups are expected to start working in mid-May.