Hostage lists published by unaffiliated MP Nadia Savchenko contain mistakes, this step however can harm their families, adviser to the SBU chief, Yuriy Tandit, has said.

"I asked Savchenko not to do this when we talked to her, she heard me," Tandit said in a comment to BBC Ukrainian.

In his words, the lists are partially "incorrect".

"The lists contain personal data of our guys. However, preliminary analysis indicates that the list is incorrect," he said.

According to the SBU representative, the publication of these lists cannot help speed up the release of the hostages. "Usually, the negotiations were efficient when no one was using them to for PR and when there as no fuss around them. Decisions on specific exchanges are made in Russia. This is not a matter of lists," Tandit said.

He warned that now scoundrels have received personal data of many Ukrainian hostages and an opportunity to blackmail their families, demanding ransom for instance.

According to Tandit, hustlers can phone the relatives posing as persons authorized by militants and promise to release a hostage for a reward.

When asked, if Savchenko can be punished for publishing these data, Tandit said he cannot talk about this yet. The advised to the SBU head also refused to comment on the list of Russians in Ukrainian captivity published by Savchenko.