ChampCar bosses Kevin Kalkoven and Gerry Forsthe said that comments made by IndyCar president Tony George, who indicated that an end to a bitter 12-year separation was "closer than ever" were highly inaccurate.
"Unfortunately, leaks and media reports about a possible unification of ChampCar and the Indy Racing League have significantly hampered discussions," said Kalkoven and Forsythe.
"Over the past three years, we have fielded and offered several proposals regarding unification of the two premier US-based open-wheel racing series, but we have been unable to reach an acceptable solution.
IndyCar-ChampCar merger close
"Discussions currently are at a standstill, and we therefore are proceeding with plans to continue as Champ Car."
The IndyCar World Series, which was the top open-wheeled series in US motorsport, was ripped apart at the end of 1995 after George - the president of the Indianapolis Motor Speedway - and team owners, became involved in a bitter dispute over money.
The result was George setting up his own series the Indy Racing League the following year, which adopted the IndyCar tag in 2003 and used the Indy 500 as its centrepiece while the owners' series CART - which later became ChampCar - went their own way.
Despite the growing momentum of IndyCar, which persuaded top teams like Penske and Ganassi over from ChampCar in recent years, both series have lost popularity to the increasingly international NASCAR Sprint Cup.
ChampCar, in particular, are having money problems, with a number of races having been cancelled over the last three years due to financial shortfalls.
George is in Japan to meet with Honda in a bid to negotiate a date change for the IndyCar race at Motegi in Japan and rubber-stamp a deal of free engines for any ChampCar teams wishing to switch to his series should a merger still go ahead.
If George, Forsythe and Kalkoven do manage to put their differences aside and go through with a merger, ChampCar, which has run since 1979 in it's various guises, will cease to be.
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