The team of Naftogaz Ukrainy has invited Yulia Tymoshenko to witness in the Stockholm arbitration, but no answer has been received, Naftogaz's Chief Commercial Director Yuriy Vitrenko has said.

"Tymoshenko did not take part in the arbitration… We asked her to be a witness, but we have not received the required consent to act as a witness defending Ukraine in the certain period of time. We did not count on Tymoshenko's help," he wrote on his Facebook page.

Vitrenko added that former head of Naftogaz Ukrainy Ihor Didenko acted as a witness.