Three former executives of Japan's disgraced Olympus Corp face possible arrest this week over their role in a $1.7 billion accounting fraud at the maker of medical equipment and cameras, Japanese media said on Thursday.

Japanese prosecutors are set to summon the trio for questioning as early as Thursday, and could make arrests if the allegations against them are firmed up in questioning, the Yomiuri and Nikkei newspapers said.

Ex-President Tsuyoshi Kikukawa, former Executive Vice President Hisashi Mori and former auditor Hideo Yamada have already been identified by an Olympus-commissioned investigative panel as the main culprits in the fraud.

They are being investigated for violations of the Financial Instruments and Exchange Law, the Nikkei said.

No official at Olympus was immediately available for comment.

Last year, the investigative panel found the trio had played leading roles in a 13-year scheme to hide the losses, and they are among 19 executives Olympus is suing over the scandal.

Kikukawa's condominium house was among 20 sites raided in December by prosecutors investigating the fraud.

The scandal was exposed last October by then-chief executive Michael Woodford, who was sacked by the Olympus board after he questioned the transactions.

The Nikkei, citing sources familiar with the official investigation, said Mori and Yamada are suspected of orchestrating the scheme to hide investment losses.

Olympus also allegedly provided false information in its financial statements for fiscal 2006 to 2010 by inflating the value of corporate buyouts to plug the hole created by the securities losses.

The Nikkei said Kikukawa, who became president in 2001, was reportedly aware of the details of the cover-up.

Olympus is also under investigation by law enforcement agencies in Japan, Britain and the United States.

(Reporting by Ranjita Ganesan; Writing by Mark Bendeich; Editing by Jean Yoon)