Ukraine's second president Leonid Kuchma has said security is the first priority issue in Donbas.

"The key issue is the problem of security. Elections won't be considered until there is peace on this land," Kuchma told reporters in Minsk.

The leaders of the self-proclaimed Donetsk and Luhansk people's republics, Alexander Zakharchenko and Igor Plotnitsky, have yet to sign the document on weaponry removal in Donbas, he said.

"The document lacks signatures by Zakharchenko and Plotnitsky. The opposite side has reassured us that the documents will be signed before Thursday through the OSCE," he said.