Ukraine should provide for transparency in coal purchases in the Anti-Terrorist Operation (ATO) zone and abroad, U.S. Ambassador to Ukraine Geoffrey Pyatt said during the Energy Diplomacy: New Challenges and Opportunities panel in Kyiv on Tuesday.

The ambassador stressed on the importance of transparency of contracts with international suppliers, for example, from South Africa and transparency in domestic trade, for example, trade with militant-controlled coalmines.

Pyatt said that the diversification of nuclear fuel supplies to Ukrainian nuclear power plants (NPPs) plays a big role for the country's energy security.

He expressed hope that Westinghouse would be able to increase its supply to Ukraine. He said that the U.S. is not trying to remove Russians as suppliers, but it is necessary to take away the instrument they use as monopolists. This concerns waste nuclear fuel as well: one of the U.S. companies, Holtec, would work with Ukraine under a very important project, he said.

Pyatt added that the gas sector reform is an important challenge for Ukraine.

"I see progress in this area. If we look forward, you should make several important steps: increased internal gas production. The Verkhovna Rada plays a big role here… secondly, greater energy efficiency," he said.