It is understood all four members of the indie band Viola Beach died in an accident, which happened on Saturday near the Swedish capitalStockholm.
The car plunged more than 25m from a highway bridge intoa canal, the police say.
The Foreign Office said it was in contact with the local authorities and supporting the families of the victims.
The Warrington-based band members were Kris Leonard, River Reeves, Tomas Lowe and Jack Dakin.
They were due to play a gig in Guildford inSurrey on Saturday, but it was cancelled.
They had been part of the line-up for Swedish music festival Where is the Music?
on Friday.