"This issue has long been discussed….it was raised last year and is part of the Minsk Agreements. And I believe this issue needs to be discussed. Unfortunately, it's not clear now how we'll be implementing it. But, in the end, one should finally start discussing and addressing this problem," Sajdik said, after a Trilateral Contact Group meeting in Minsk on Wednesday.

The creation of the subgroup is an initiative of Ukraine.

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The next Trilateral Contact Group meeting in Minsk is slated for July 27, Sajdik said.