Ukrainian Prime Minister Arseniy Yatseniuk has ordered concerned agencies and companies to step up the security of the Ukrainian gas transport system (GTS).

"I am asking the Interior Ministry, SBU, NJSC Naftogaz and Ukrtransgaz to urgently tighten the security of Ukrainian gas pipelines. We predicted a few weeks ago that there would be subversive acts aimed at undermining Ukraine's reputation as a reliable transit country," he said, while opening a government meeting on Wednesday.