Irish screenwriters Brian O'Malley and Terry McMahon have won the Hartley-Merrill Prize for International Screenwriting at Cannes.

O'Malley and McMahon won the award for their screenplay 'Sisk', which also won the Irish Film Institute's fourth Tiernan MacBride Award for Screenwriting this year.

The script competed against over 2000 entries from 23 countries. This is the first time an Irish screenplay has won the award.

Chairman of the prize, Ted Hartley, called 'Sisk' "a skilfully written piece about the Chinese Mafia in Dublin".

Terry McMahon, who accepted the award, said he and his co-writer Brian O'Malley were overwhelmed at the success of the screenplay, which tells the story of an ex-gangster who returns home to atone for his sins but finds himself entangled in his violent past.