Expendables 2 movie has continued its grip on the North American box office chart, holding onto the number one spot for a second consecutive week.

The movie, which sees action stars including Sylvester Stallone, Arnold Schwarzenegger and Bruce Willis reunite, took $13.5 million.

The Bourne Legacy remained at two in its third week of release, with $9.3m.

Stop-motion comedy ParaNorman, about a boy who helps save his town from a zombie invasion, was at three.

Typical of late summer openings, other new releases performed weakly in the chart.

Expendables 2 movie has continued its grip on the North American box office chart, holding onto the number one spot for a second consecutive week

Thriller Premium Rush, starring Joseph Gordon Levitt as a bike messenger chased through New York by a policeman who wants an envelope he’s carrying, opened at seven with $6.3 million.

And low-budget road-chase comedy Hit & Run, starring real-life couple Dax Shepard and Kristen Bell, entered at 10 with $4.7 million.

With less competition from big Hollywood films, it allowed anti-President Barack Obama documentary, 2016: Obama’s America, to land at number eight.

After opening in limited release in July, it expanded nationwide ahead of the Republican National Convention to formally nominate Mitt Romney as Barack Obama’s challenger in the presidential race.

The film is a conservative critique envisioning what the US would look like four years from now if Barack Obama was re-elected.

“It’s extremely rare for a documentary to break into the top 10, but August can be a land of opportunity for smaller films,” Paul Dergarabedian, box office analyst for Hollywood.com said.

“Also, there’s the fact that this is a very conservative film. Normally, it’s Michael Moore-branded documentaries, the liberal documentaries, that make all the money.”

The film has so far taken $9.1 million domestically, but the figure is still far away from other political documentaries – Michael Moore’s Fahrenheit 9/11 opened at number one with $23.9 million in June 2004, and went on to become the US’s top-grossing documentary taking $119.1 million.

 [youtube cZEWSelOmA8]