The French carmaker Renault has named a temporary chief executive following the arrest of Carlos Ghosn.
Renault said its chief operating officer, Thierry Bolloré, would step up to the role because Mr Ghosn was "temporarily incapacitated".
Mr Ghosn was arrested in Japan on Monday after allegations of financial misconduct.
As well as Renault, he is also the chairman of both Nissan and Mitsubishi Motors and leads an alliance of the three carmakers.
Japanese prosecutors allege he under-reported his income from Nissan by about $US45 million over five years and using company assets for personal purposes.
Following an emergency board meeting, Renault said Mr Ghosn would remain as its chairman and chief executive.
But it said Mr Bolloré would lead the firm with the same powers as Mr Ghosn.
The Renault board said it was unable to comment on the allegations against him.
Meanwhile, the Financial Times reported that Mr Ghosn was planning a merger between Renault and Nissan but that the Japanese company was opposed to a deal.
Mr Bolloré is already in charge of many day-to-day activities at Renault.
The company said its decision to name him as deputy chief executive was a "transitional governance" measure "to preserve the interests of the group and the continuity of its operations".
Earlier, French Finance Minister Bruno Le Maire said Mr Ghosn was "no longer in a position" to lead the carmaker in which the French state has a 15% stake.
He also said Renault's partnership with Nissan remained in the interests of both France and Japan and of both companies.
Nissan and Mitsubishi are both preparing to remove him from his posts.
But Mitsubishi Motors chief executive Osamu Masuko said the alliance would be difficult to manage without Mr Ghosn.
Nissan has a 34% controlling stake in the smaller Japanese carmaker.