Josh Hartnett's vampire action film 30 Days Of Night is no sucker at the U.s. box office - it has claimed the number one spot in its first weekend on release.

The movie, in which Hartnett and Melissa George play cops fighting the undead in remote Alaska, toppled Tyler Perry's Why Did I Get Married? with a first-weekend take of $16 million.

Former number one The Game Plan slipped another spot to three, while George Clooney's drama Michael Clayton claimed fourth place for a second week.

Ben Affleck's much-hyped and critically-acclaimed directorial debut Gone Baby Gone failed to impress cinemagoers, making just $6 million in its opening weekend, and debuting at three, just ahead of sports spoof The Comebacks, which enters the box office countdown at six.