MOSCOW, June 11 (Reuters) - The head of the Organisation for Security and Cooperation in Europe on Wednesday called for the immediate release of eight OSCE monitors who went missing amid the turmoil in eastern Ukraine around two weeks ago.
The security and rights watchdog lost contact with two of its international monitoring teams late in May amid intense fighting between the Ukrainian army and pro-Russian fighters engulfing the eastern flatlands of the former Soviet republic.
"I find this unacceptable. I think we should all keep insisting on their immediate and unconditional release," OSCE Secretary General Lamberto Zannier told a meeting with Russian Foreign Minister Sergei Lavrov in Moscow.
An OSCE spokesman in Kiev said earlier in June that the organisation was in talks with various armed groups on the ground for the release of the monitors, who were believed to be in good shape.
Two groups of four monitors each went missing in eastern Ukraine late last month, one in the Donetsk region on May 26 and one north of the city of Luhansk on May 29. Some senior separatist leaders have also promised to set them free.
But the OSCE has so far not been able to reestablish contact with its missing teams, one of which also includes a fifth person, a Ukrainian translator.
Making the task even more difficult is the proliferation of numerous armed groups fighting in the region, with poor communication and coordination as well as some rivalry and power struggles between them.
Illustrating the high risks for foreigners in the area, another group of 11 OSCE staff was held for several hours outside of Donetsk on May 28th by what they said was a Cossack unit. They were later released.
Lavrov told the meeting Russia was providing "humanitarian aid" to violence-hit regions through pro-Russian fighters after Kiev refused to allow such deliveries from Russia on its territory.
The Vienna-based OSCE is also mediating between Kiev and Moscow to help agree a peace plan for Ukraine. (Reporting by Gabriela Baczynska; Editing by Tom Heneghan)