Ukraine's oil and gas company Naftogaz Chief Executive Officer Andriy Kobolyev (L) and Ukraine's Minister of Foreign Affairs Pavlo Klimkin (R) give a joint press conference after a meeting with the European Commission vice-president in charge of Energy Union and Russian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)

Ukraine's oil and gas company Naftogaz Chief Executive Officer Andriy Kobolyev looks on during a press conference after a meeting with the European Commission vice-president in charge of Energy Union and Russian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)

Ukraine's Minister of Foreign Affairs Pavlo Klimkin talks during a press conference after a meeting with Russian and Ukrainian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)

Ukraine's oil and gas company Naftogaz Chief Executive Officer Andriy Kobolyev (L) and Ukraine's Minister of Foreign Affairs Pavlo Klimkin (R) give a joint press conference after a meeting with the European Commission vice-president in charge of Energy Union and Russian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)

Ukraine's oil and gas company Naftogaz Chief Executive Officer Andriy Kobolyev talks during a press conference after a meeting with the European Commission vice-president in charge of Energy Union and Russian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)

Ukraine's oil and gas company Naftogaz Chief Executive Officer Andriy Kobolyev talks during a press conference after a meeting with the European Commission vice-president in charge of Energy Union and Russian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)

Ukraine's oil and gas company Naftogaz Chief Executive Officer Andriy Kobolyev talks during a press conference after a meeting with the European Commission vice-president in charge of Energy Union and Russian representatives at the EU headquarters in Brussels on January 21, 2019. (Photo by John THYS / AFP)