WEC chief Gerard Neveu says Formula 1's decision to schedule the Baku race on the same weekend as the 2016 Le Mans 24 Hours is a "clear attack" on his series.
In years gone by several Formula 1 drivers have contested the Le Mans 24 Hours race, arguably one of the most prestigious events on the motorsport calendar.f
This season it was even won by a current driver as Nico Hulkenberg's Porsche team took the chequered flag ahead of former F1 driver Mark Webber and his Porsche team-mates.
Hulkenberg, though, won't have the opportunity to defend his title in 2016 due to a calendar clash between Baku and Le Mans.
"It's a clear attack on us and on the race," Neveu told Autosprint magazine. "(Bernie) Ecclestone never does anything nonchalantly.
"It is a shame because by doing this you take away the possibility of having F1 stars entering what still is the most important race in the world.
"We could have had Hulkenberg and also other F1 drivers – motorsport fans are losing out."