Formula 1 drivers want guarantees about the safety of Pirelli's tyres at the Belgian Grand Prix in the wake of the failures that hit Sebastian Vettel and Fernando Alonso on Friday.
Amid concerns about the dangers of potential tyre failures at the high-speed Spa Francorchamps circuit, F1's leading drivers have asked the FIA to get assurances from Pirelli about the safety of its products.
Although Pirelli is adamant that the problems that Vettel and Alonso suffered were caused by debris puncturing their right rears, drivers and team figures are not so convinced that is the full explanation.
No repeat of British GP drama - Pirelli
During Friday evening's drivers' briefing at Spa, F1 race director Charlie Whiting was asked to look in detail at the Pirelli matter and get the Italian company to guarantee that there is no structural issue with the tyres.
Just two races after the Grand Prix Drivers' Association (GPDA) threatened to withdraw from the German GP if there were tyre problems, the drivers remain concerned about the possibility of a repeat of what happened at Silverstone.
A spate of tyre blow-outs marred the British Grand Prix and forced Pirelli to revert to last year's construction to prevent repeat problems.
One leading driver said that there was serious concern from the drivers about the situation, but made it clear they are prepared to leave the matter to Whiting's jurisdiction.
"We've left it in Charlie's hands," said the drivers. "We have to trust him."
Pirelli motorsport director Paul Hembery admitted on Friday that the fact there had been failures on Friday at Spa had been a concern.
"It is a worry for the sport because we have to go out and find what it is," he said.
"There is not a lot we can do, but we will try our very best to identify it to give us an indication of what is causing it."
Pirelli plans to conduct a detailed examination of the Spa track to try to get to the bottom of exactly what punctured Vettel and Alonso's tyres.
Red Bull's Mark Webber said that drivers wanted clarity from Pirelli about the situation, as they were not satisfied with the response they had got so far.
"We need answers and 'debris' is not the answer," he said.
Whiting met with Hembery and Pirelli racing manager Mario Isola to inspect both the tyres and the failures.
Whiting plans to conduct a detailed investigation tonight.