Mark Wahlberg (l) plays one of four adopted siblings in Four Brothers

Directed by John Singleton of Boyz N The Hood fame, the thriller took $20.7m (�11.4m) between Friday and Sunday.

The Skeleton Key opened in second place with takings of $15.8m (�8.7m).

The total takings of the top 12 films were down 16% on the same weekend last year when Alien vs Predator made $38.3m (�21.1m) in its first three days.

Decline

But the decline pales in comparison to the 19-week slump earlier this year.

"It was a fairly unremarkable weekend," said Paul Dergarabedian, president of box office tracking company Exhibitor Relations.

"August usually is a slowdown month," he added.

US AND CANADA BOX OFFICE 1. Four Brothers $20.7m (�11.4m) 2. The Skeleton Key $15.8m (�8.7m) 3. The Dukes of Hazzard $13m (�7.2m) 4. Wedding Crashers $12m (�6.6m) 5. Deuce Bigalow: European Gigolo $9.4m (�5.2m) Source: Exhibitor Relations

Comedy sequel Deuce Bigalow: European Gigolo entered the chart at five, performing poorly compared to the original.

It took $9.4m (�5.2m), rather less than its star Rob Schneider had thought. He told US "shock jock" Howard Stern his film would make $20m (�11m) in its opening weekend.

Comedian Johnny Vaughan and pop star Rachel Stevens make cameo appearances in the film, which cost a modest $22m (�12m) to make.

Wildlife documentary March of the Penguins continued to perform well, its $6.7m (�3.7m) haul taking its cumulative takings to $37.6m (�20.7m).

The weekend's only other new release, Second World War drama The Great Raid, opened in tenth place, with weekend takings of $3.4m (�1.8m).