Irish rider Derek Brien has been killed in an accident at the Isle of Man TT.
The 34-year-old from County Meath crashed at Gorse Lea on the second lap of today's Supersport race, which was subsequently red-flagged.
An investigation into the circumstances of the accident is under way.
A statement by race organisers read: "ACU Events Ltd regrets to announce the death of Derek Brien, 34, from Co. Meath in Ireland who was killed during the first Supersport race at the 2011 Isle of Man TT Races following a high-speed accident at Gorse Lea.
"Derek was an experienced road racer who first competed on the Isle of Man in the Manx Grand Prix in 2007 and competed in the TT Races in 2009 and 2010. He had a highest TT place of 13th in the 2010 Supersport 1 race.
"Derek was single with a partner, Sarah. The ACU wishes to pass on their deepest sympathy to Derek's family and friends."
ACU Events managing director Jim Parker added: "Derek was a very talented road racer and achieved a number of notable career highlights including his Manx Grand Prix victory.
"He will be sorely missed."
Brien, who won the junior race at the Manx Grand Prix on the Isle of Man four years ago, is the third competitor to be killed at this year's event.
Sidecar competitor Bill Currie, 67, and his passenger Kevin Morgan, 59, died in a crash in qualifying last Tuesday.