Here's what he had to say, thanking his longtime fanbase for their support of the R rated franchise adventure, which landed on Blu-ray and DVD January 14th. (Warning, you have to get past about 3 minutes of Vin dancing and lip-syncing before he drops the news).
Universal has released no official statement that a Riddick sequel is in the works. Nine years passed between The Chronicles of Riddick and Riddick as the actor and his director/co-creator David Twohy struggled to get this latest saga made. There is no telling how much time will pass between this release and the next one, but it shouldn't be as long of a wait.
Riddick was released September 6th, 2013 and stars Vin Diesel, Jordi Mollà, Matthew Nable, Katee Sackhoff, Dave Bautista, Bokeem Woodbine, Raoul Trujillo, Conrad Pla. The film is directed by David Twohy.