Mercedes look poised to increase their involvement with Brawn
Car giant Mercedes-Benz is in talks about buying a shareholding in championship leaders Brawn Grand Prix.
The German company, which owns 40% of McLaren, is considering taking a major interest in Brawn.
McLaren, the team world champion Lewis Hamilton drives for, said they were "supportive of our partner's plans re engine supply of other teams".
Brawn refused to comment while Mercedes told BBC Sport that "our company is not in a position to comment".
The full statement from a Mercedes spokesman read: "Our co-operation with various Formula 1 teams obviously gives rise to various rumours, but we would like to ask for your understanding that our company is not in a position to comment.
"The facts are we have a long-term contract with our partner McLaren with whom we won the last F1 world championship."
Brawn are leading the drivers' championship with Jenson Button heading into this weekend's Italian Grand Prix.
BBC Sport understands that the deal, if it happens, would not be a threat to Mercedes's continued relationship with McLaren.
A McLaren spokesman added: "Mercedes-Benz's engine supply contract with McLaren is a very long-standing one - it's in its 15th consecutive year, in fact - and it will continue to run for many years to come.
"However, we're supportive of our partner's plans re engine supply of other teams in Formula 1 and we were delighted earlier this year that a Mercedes-Benz engine supply deal was able to be done with Brawn, thereby saving that team from likely extinction.
"Force India, too, has blossomed as a result of its engine supply/engineering consultancy collaboration with Mercedes-Benz and McLaren - as Giancarlo Fisichella's impressive second place in the recent Belgian Grand Prix showed all too clearly.
"Both McLaren and Mercedes-Benz remain extremely satisfied with our F1 collaboration, which has netted three drivers' world championships and one constructors' world championship as well as dozens of grand prix victories.
"As ever, we'll be aiming to add to that win tally together at this weekend's Italian Grand Prix - although we never underestimate our opposition and the competition will undoubtedly be tough."
Mercedes were instrumental in the establishment of the Brawn team, which was set up out of the ashes of Honda after the Japanese manufacturer pulled out of F1 last December.
Mercedes could end up owning shares in Brawn and McLaren
The apparent desire of Mercedes to extend its commitment to F1 is in contrast to the behaviour of several other road-car manufacturers.
As well as Honda, BMW last month announced it would quit F1 at the end of this season, and Toyota is waiting until November to sign off its F1 budget for 2010.
And Renault F1 boss Flavio Briatore has rejected speculation about the future of his team in the sport.
It is not clear what effect any deal with Brawn might have on the other F1 teams supplied with Mercedes engines.
New rules allow engine manufacturers to supply up to three customer teams next season, so in theory Mercedes could continue with McLaren, Brawn and Force India, while adding a fourth team in Red Bull, who are known to be keen to switch to Mercedes in 2010.
But sources say Mercedes may be less keen to supply Red Bull, who are Brawn's main title rivals this season, if the Brawn shareholding deal is sealed.
The supply of Force India, who use Mercedes engines and have a technology transfer deal with McLaren, may also come under scrutiny.
The talks between Mercedes and Brawn come as the team heads into a tense climax to the F1 season.
Button and Brawn dominated the early part of the season, with the Englishman winning six of the first seven races.
But Button failed to get on to the podium in the succeeding five grands prix and heads into the final five events of 2009 needing to regain his form.
He leads Brawn team-mate Rubens Barrichello by 16 points, with Red Bull's Sebastian Vettel a further three points adrift. Vettel's team-mate Mark Webber is 20.5 points behind Button.
There are a maximum of 50 points available in the remaining five races of the season.