Discontent is brewing over F1’s proposed calendar for 2016.
After the most recent meeting of the World Motor Sport Council, the FIA declared that a 21-date provisional schedule for next year "was approved".
Sauber boss Monisha Kaltenborn, however, expressed concerns that stretching beyond an agreed limit of 20 races will require "additional staff and resources".
And Red Bull’s Christian Horner added: "Tough for the whole factory not to have a summer break. I think it’s important that we have one."
When asked about the loss of the summer break and pushing beyond 20 races, an unnamed boss from the F1 midfield told Auto Motor und Sport: "Both are violations of the regulations.
"So it is only possible if all the teams agree. And not all of them do."
The report added, however, that no team has lodged a formal complaint so far.
That could be because it is only a provisional calendar, and quite often a race or two is dropped before a season’s ultimate schedule is finalised.
Germany, for instance, is scheduled to return in 2016 after a break this year.
But Ecclestone said: "I don’t know what’s going to happen with Germany. We have a contract, so if they honour the contract, they should be there."
Another endangered race is Monza.
"Probably Monza," Ecclestone said when asked by Spain’s Movistar F1 if one of the proposed 21 races could be dropped.