Updated

Ukrainian investigators have detained an influential former lawmaker suspected of embezzlement.

The National Anti-Corruption Bureau said late on Thursday that it is preparing to file charges against Mykola Martynenko, former chairman of the parliament's energy and fuel committee, on suspicion of embezzling $17.3 million in arranging purchases of uranium ore concentrate for a state-owned company which provides uranium for the country's nuclear power stations.

Martynenko, a top ally of former prime minister Arseny Yatsenyuk, had served in the Ukrainian parliament since 1998 but stepped down in December following reports of his involvement in money laundering in Switzerland. Martynenko has often been described as the financier behind Yatsenyuk's People's Front party.

Martynenko is expected to face a court hearing later on Friday on his possible arrest.