The FIA has revealed that it received 15 entries from new teams to enter Formula 1 next year.
In the wake of the announcement that Campos Grand Prix, Team US F1 and Manor Grand Prix have been granted unconditional entries to next year's championship, the FIA also says discussions are continuing with other outfits in case current teams choose to leave.
In a statement issued on Friday, the FIA said: "When the FIA opened entries for the 2010 FIA Formula One World Championship, it received applications from 15 potential new teams.
"All of those entries underwent a stringent due diligence process to ensure that new teams have the required level of funding, resources, experience and technical expertise to compete at the highest level of motor sport.
"Three of those teams have been confirmed for 2010 and further due diligence is currently taking place on other potential entries."
The FIA also revealed details of the three successful new teams.
Campos Grand Prix's headquarters will be in Madrid, while its technical centre will be at Campos Racing's current headquarters in Valencia. The team will be powered by Cosworth engines, and its car will be built by Dallara.
Manor Grand Prix is a tie-up between Manor Motorsport and Wirth Research Limited; with former team boss Nick Wirth acting as technical director below team owner John Booth.
Team US F1 is being run by Ken Anderson and Peter Windsor, and will be based in Charlotte in the United States.