The future of the United States Grand Prix is in doubt after the Indianapolis circuit confirmed that it would not host next year's race.

Indy boss Tony George and Bernie Ecclestone had been attempting to negotiate a new deal after the current contract expired following the 2007 GP, but could not come to an agreement.

"After several discussions, Bernie Ecclestone and I were unable to agree how to keep Formula One in Indianapolis for the near term," said George.

But he suggested that the Formula 1 could return to Indianapolis after 2008.

"We have agreed to leave the door open for a potential future date," he said.

"It has been a pleasure having the United States Grand Prix at Indianapolis, and I hope that as we approach our Centennial Era at the Indianapolis Motor Speedway, an opportunity might present itself that would allow its return."

The breakdown in talks potentially leaves next season's world championship without a USA date.

Although rumours had circulated that Ecclestone was investigating alternative American options, it is not thought that any would be ready for next season.

The relationship between Indy and F1 became strained after tyre safety concerns forced all bar the six Bridgestone cars to pull out of the 2005 US Grand Prix.

After the demise of a series of unsuccessful street course events in the 1980s and early 1990s, F1 did not have a US round between 1991 and 2000, when it made its debut on the newly-constructed Indianapolis infield track.

Source:ITV.com/F1

Spyker has announced that it has split with Christijan Albers with immediate effect.

The Dutch driver had been under pressure all season after struggling to match his rookie team-mate Adrian Sutil's pace, but a team statement said that he had ultimately been dropped after a sponsor defaulted.

"This has been a very difficult decision," said team boss Colin Kolles.

"Christijan has started to find some form in the car, but the team's ambitious development programme has been seriously compromised by non-payment by one of his sponsors and we are faced with no other option."

There had been speculation for several months that Albers might not see out the season with Spyker.

He had been out-qualified by Sutil seven times in nine races, and had made a number of errors - most notably his pit stop disaster at Magny-Cours.

But Spyker's Formula 1 director Michiel Mol was adamant that Albers' performance was not the issue.

"The decision to replace Christijan is one of the hardest I have had to take since becoming involved in the team," Mol said.

"By terminating the contract with Christijan and the subsequent entering into a new contract it enables Spyker F1 Ltd. to safeguard its strong financial footing needed to fulfil its technical and commercial goals.

"We would also like to stress this decision has nothing to do with Christijan's recent performances - we still have faith in his contribution as a driver - but the long-term future of the team is of paramount importance.

"We would like to thank Christijan for his input and wish him every success in the future."

Spyker has not yet announced who will replace Albers.

Honda reserve Christian Klien has been linked to the drive.