KIEV, May 16 – Gazprom CEO Alexei Miller on Thursday met a top Ukrainian official in Moscow amid growing concerns that Ukraine has been increasingly refusing to import Russian gas and replacing it with European supplies.

Yuriy Boyko, deputy prime minister for energy, traveled for a meeting with Miller “to discuss current gas supplies,” according to Gazprom report.

Ukraine, once the largest market for Gazprom, has reduced imports of Russian gas dramatically over the past three months.