Jackson plays an FBI agent escorting a witness to Los Angeles

But the film's modest takings of $15.3m (�8.1m) only took it marginally ahead of last week's champion, Will Ferrell's motor racing comedy Talladega Nights.

The Samuel L Jackson film was expected to perform better off the back of the wave of hype that preceded its release.

The $30m (�15.9m) action movie was released at the same time in the UK without being screened to critics.

The film's weekend tally includes $1.4m (�740,757) takings from preview screenings held on Thursday night, according to studio estimates.

If these are not taken into account, Talladega Nights: The Legend of Ricky Bobby is still the top film in the US and Canada.

NORTH AMERICAN BOX OFFICE 1. Snakes on a Plane 2. Talladega Nights: The Ballad of Ricky Bobby 3. World Trade Center 4. Accepted 5. Step Up 6. Barnyard: The Original Party Animals 7. Little Miss Sunshine 8. Pirates of the Caribbean: Dead Man's Chest 9. Material Girls (above) 10. Pulse Source: Exhibitor Relations

Oliver Stone's 11 September drama World Trade Center held steady in third place with weekend takings of $10.8m (�5.7m).

The comedy Accepted, about a teenager who sets up his own fake college after he fails to secure a place at a real one, made its debut at number four, earning $10.1m (�5.3m).

The only other new entry in this week's Top 10 is Material Girls, a comedy starring pop star Hilary Duff and her older sister Haylie.

The film opened in ninth place with weekend takings of $4.6m (�2.4m).

The Pirates of the Caribbean sequel, Dead Man's Chest, dropped two places to eight but remains the most profitable film in this week's rundown.