Formula One teams were meeting FIA president Max Mosley today for 11th-hour talks to try and end a standoff over entries for next season that could tear the sport apart.
Team sources confirmed the talks in London after the eight-member Formula One Teams Association (FOTA) met the previous day.
The governing International Automobile Federation is due to publish its official 2010 entry list on Friday, with champions Ferrari and others threatening to walk away unless the rules are rewritten.
Mosley wants to bring in new teams to help the sport overcome the credit crunch and the possible departure of some manufacturers.
The published 2010 rules have put forward an optional 40 million-pound ($65.62 million) budget cap, with those accepting it given greater technical freedom, to help new teams come in and existing ones cut costs.
However, Ferrari, former champions Renault, Toyota and the two Red Bull teams oppose the budget cap and any two-tier system.
The eight FOTA teams have all submitted conditional entries, subject to the 2009 rules remaining in place and a new commercial Concorde Agreement being signed by Friday.
Former champions Williams and tail-enders Force India have entered unconditionally while at least 10 would-be new teams have applied.
FOTA have said a rival series is being considered only as a last resort but have been reluctant to say what they would do if omitted from the published list.
The standoff has been going on for weeks, with Mosley last meeting the teams during the Monaco Grand Prix in May when nothing was decided.
Mosley wrote to Ferrari president Luca di Montezemolo, who also chairs FOTA, after that meeting however to offer a number of compromises.
In the May 26 letter, seen by Reuters, he said there must be a budget cap but it could be as high as 100 million euros in 2010 before going down to 45 million in 2011.
"We can agree that all teams race under the same 2010 rules," he added. "These would be as published, but with the technical and sporting advantages originally offered to cost-cap teams deleted."
To help new teams, the transfer of know-how from existing teams would be facilitated in 2010 and possibly 2011. One employee, as well as the drivers, would remain outside any budget cap from 2011.
That measure would help teams who have highly-paid designers, such as Red Bull's Adrian Newey.
Mosley said the FIA was also prepared to negotiate a new Concorde Agreement along the lines of a draft sent by the teams, and would be happy to call the cost cap "financial regulations" if that was more palatable.