Two riders were killed in separate accidents during Thursday's racing at the Southern 100 on the Isle of Man, in the Irish Sea between Britain and Ireland.
The BBC reported that Mark Madsen-Mygdal, 23 and from the island, died following a crash on the last lap of the 600cc Supersport race.
Paul Thomas, a 58-year-old father and also from the Isle of Man, was killed in an accident during the Sidecar Championship race.
Three riders have been killed at the Southern 100 this year as David Jukes died in Monday's practice.