KYIV — Top corruption watchdogs said they carried out dozens of raids Monday across Ukraine during an investigation into the energy sector.

The National Anti-Corruption Bureau of Ukraine (NABU) and the Special Anti-Corruption Prosecutor’s Office (SAP) are probing top officials at Ukraine’s state energy companies, including nuclear energy operator Energoatom.

Searches took place two days after Russia launched its largest attack yet against the Ukrainian energy system, including nuclear plants and electric substations, and hammered power operator Сentrеgenergo’s electricity-generating capacity.

Lengthy blackouts are still occurring throughout the country, as authorities struggle to restore power, while Ukrainians question whether energy facilities were properly protected from Russian attacks.

NABU said its 15-month investigation and 1,000 hours of wiretapping involving the bureau’s entire staff culminated Monday in 70 raids.

Some of the wiretappings were from July, the same month Ukraine’s government and parliament tried to strip NABU of its independence and bring it under political control, citing Russian influence on the bureau — in a move that was later reversed following nationwide protests.

NABU refused to reveal the names of the main suspects in the corruption probe, but said there were noted businesspeople and energy officials among the alleged perpetrators. 

The main goal of the scheme they co-organized, according to NABU, was to obtain illegal benefits amounting to 10-15 percent of a state contract value — theoretically running into the millions of euros — from counterparts of Energoatom, including companies involved in building protective structures for energy infrastructure.

Energoatom declined to comment due to the ongoing investigation.