Universal is developing a sequel to 'The Purge'.

The Ethan Hawke-starring horror film was a surprise hit at the US box office this past weekend, topping the chart with $36.4 million in ticket sales, and now the movie studio are hoping to capitalise on the flick's success with a follow-up.

Producer Jason Blum confirmed the news on Twitter, writing: ''The Purge 2 is in development @UniversalHorror #ThePurge (sic)''

'The Purge', which was produced on a modest $3 million budget, proved to be highly profitable in its opening weekend and fended off strong competition from big budget blockbusters such as 'Fast & Furious 6' and Will Smith's 'After Earth'.

The futuristic horror flick is set in the US, where, for one night a year, all crime - including murder - is legal. The film centres on Ethan Hawke's James Sandin and his wife Mary, played by 'Game of Thrones' actress Lena Headey, who try to protect their family from home invaders during the annual purge.

The low-budget film was produced by Universal, Blum's Blumhouse Productions and 'Transformers' director Michael Bay's Platinum Dunes company.

Blum is also known for producing recent horror success stories including the 'Paranormal Activity' franchise, 'Insidious' and 'Sinister', which also starred Hawke.