NUERBURGRING, Germany (REUTERS) - Formula One drivers will withdraw from this weekend's German Grand Prix (GP) if the tyre explosions which marred Sunday's British race occur again, the Grand Prix Drivers' Association said on Thursday.

During news conferences before the German race, drivers had sounded confident that tyre providers Pirelli had sorted out the problems. However, following a later meeting of the drivers'union in the Nuerburgring paddock, the tone hardened.

"The drivers of the Grand Prix Drivers' Association wish to express their deepest concerns about the events that took place at Silverstone," a statement said.

"We trust that the changes made to the tyres will have the desired results and that similar problems will not occur during the German GP weekend.

"We are ready to drive our cars to the limit, as we always do, and as it is expected by our teams, sponsors and fans.

"However, the drivers have decided that, if similar problems should manifest themselves during the German GP, we shall immediately withdraw from the event, as this avoidable problem with the tyres endangers again the lives of drivers, marshals and fans."

Five drivers suffered blowouts on Sunday with a piece of tyre narrowly missing the head of Fernando Alonso of Ferrari, heightening fears of injury after team mate Felipe Massa was badly injured after being struck on the helmet by a spring in 2009.

After the intervention of the governing FIA, following talk of a driver boycott, Pirelli have brought different rear tyres to the Nuerburgring with an inner belt made of the synthetic fibre Kevlar rather than steel.