Rumours of a McLaren-Honda divorce were already rife, but now there are claims Honda is considering pulling out of its 2018 customer deal with Sauber.
“This is the first matter I will work on,” new Sauber boss Frederic Vasseur told L’Equipe.
“Given what I’ve heard from McLaren, it’s frightening.”
Germany’s Auto Motor und Sport said Honda executives will meet in October to discuss the future of its troubled F1 collaboration.
But a Honda spokesperson told the Spanish daily Marca: “We are not considering any option other than continuing in F1 with McLaren next year.
“It is not true that we are evaluating the possibility of stopping. We are going to fulfil the contract that we have.”
As for the Sauber rumours, however, Honda said: “We have no comment on this.”
Former F1 supremo Bernie Ecclestone told Brazil’s Globo: “I think it (McLaren-Honda) is like a marriage that has entered a very difficult phase.
“Whether they will separate or not, who knows?”