Ukraine’s National Anti-Corruption Bureau said Tuesday it has detained five individuals and identified seven other suspects in a major corruption investigation involving alleged kickbacks totaling around $100 million in the country’s energy sector.

The bureau did not name the suspects but indicated they include a businessman believed to be the mastermind, a former advisor to the energy minister, and an executive from the state-owned atomic energy company Energoatom. The probe follows a 15-month investigation into suspected graft across the sector, including at Energoatom, which produces more than half of Ukraine’s energy supply.

The alleged scheme involved suppliers being forced to pay bribes of 10% to 15% of contract values to continue providing goods and services, while high-ranking officials reportedly used their positions to control personnel decisions, procurement processes, and the flow of financial resources. Energoatom stated the investigation has not disrupted production or operational safety.

President Volodymyr Zelenskyy praised the investigation, calling anti-corruption measures “an urgent need” and urged officials to fully cooperate with investigators. Zelenskyy has faced public pressure over corruption, including reversing a controversial law last month that would have limited the independence of Ukraine’s anti-corruption watchdogs.

The investigation comes as Ukraine continues to endure Russian attacks on its energy infrastructure. The Energy Ministry reported overnight strikes in the Kharkiv, Odesa, and Donetsk regions, with scheduled power outages affecting most regions.

Meanwhile, Ukraine’s military claimed Tuesday that its long-range drone campaign targeted two Russian oil refineries—Saratov and Orsknefteorgsintez—and an oil terminal in Feodosia, Russian-occupied Crimea, aiming to disrupt revenue for Moscow’s war effort. In response, Russia’s FSB said it had foiled a Ukrainian plot to recruit Russian pilots and hijack a MiG-31 fighter jet armed with a hypersonic Kinzhal missile, though no evidence was provided and Ukrainian officials did not comment.

Ukraine’s anti-corruption drive continues to focus on rooting out entrenched graft, particularly within state-owned enterprises, as Kyiv pursues EU membership amid the ongoing war.