Turkish police have detained three top energy officials as part of a widening investigation into allegations of corruption, state news agency Anatolin reported on Monday.

Acting on orders from state security prosecutor Talat Salk, police detained Osman Nuri Dogan, head of the Turkish Electricity Distribution Corporation (TEDAS), and two senior TEDAS officials. The move comes a week after Salk charged 15 people, including former senior energy ministry officials, with corruption linked to energy tenders.

Dubbed ‘White Energy’, the investigation has so far led to the resignation of energy minister Cumhur Ersumer, although he denied allegations that he illegally steered millions of dollars in government contracts to favoured companies.