Istanbul - The future of Formula One racing in its current form remains in doubt over a budget cap row, BMW motorsport chief Mario Theissen said on Thursday.

Theissen said that the situation remained "critical" even though the teams organized in the FOTA union have provisionally registered for 2010.

"I hope that we can find a solution," Theissen said in Istanbul where the Turkish Grand Prix takes place on Sunday.

The ruling body FIA and its president Max Mosley aim to introduce a 45-million euro budget cap for 2010. The teams oppose this measure and have called for a reduction of costs in several stages.

The FIA plans to name the 13 teams for 2010 on June 12.

Mosley on Wednesday dismissed hopes of a quick peace and Theissen said that the row has by now reached a dimension beyond its original theme and that each side must also save face in any solution.

"An extreme amount of politics is involved. The stage is good, the various players are very strong. It can not be in the interest of one player to smash everything," said Theissen. (dpa)