Action comedy Tropic Thunder has retained the number one spot at the US box office for the third week in a row.

The Dreamworks/Paramount picture, featuring Ben Stiller, Robert Downey Jr and Jack Black among a group of actors whose efforts to make a Vietnam film are hampered when they are abandoned in a real war zone, took $11.5 million (£6.4 million) to crown a third week at the top of the charts.

Babylon AD, the new Vin Diesel sci-fi film opened at number two after its first weekend on release while The Dark Knight continues to perform strongly, climbing one place to third after its seventh weekend.

The Batman Begins sequel has now earned more than $502 million (£277.9 million), becoming only the second picture in history to cross the $500 barrier (£276.8 million), after Titanic.

Sony's comedy The House Bunny fell two places to fourth while political thriller Traitor and spoof film Disaster opened at five and seven, respectively.

Woody Allen's new effort, Vicky Cristina Barcelona, starring Scarlett Johansson, Penelope Cruz and Javier Bardem, rounded off the top ten with just over $3 million (£1.67 million) in its first three days on release.

The top ten films at the US box office are: (last week's position)

1 Tropic Thunder (1)
2 Babylon AD (-)
3 The Dark Knight (4)
4 The House Bunny (2)
5 Traitor (-)
6 Death Race (3)
7 Disaster Movie
8 Mamma Mia! (8)
9 Pineapple Express (6)
10 Vicky Cristina Barcelona (-)

01/09/2008 08:45:27