Science-fiction thriller "Elysium" took top spot in the North American box-office this weekend, beating out competition from raunchy Jennifer Aniston comedy "We're The Millers," estimates showed Sunday.

Starring Matt Damon and Jodie Foster, "Elysium" is set in a dystopian future where the poor have been left to inhabit a ruined Earth while the rich live on a luxurious space station.

The movie, written and directed by South African filmmaker Neil Blomkamp ("District 9"), earned $30.5 million in its opening three days, estimated figures from box-office tracker Exhibitor Relations showed.

In second place was Aniston's R-rated comedy "We're The Millers," which stars the former "Friends" actress and Jason Sudeikis in a romp about a bogus family attempting to smuggle drugs into the United States from Mexico.

The film took $26.6 million over the three-day weekend, placing it just ahead of Disney's latest animated offering "Planes."

An effective spin-off of the hugely successful "Cars" franchise, "Planes" took $22.5 million to place third.

Fourth place was occupied by another debutant, "Percy Jackson: Sea of Monsters", the latest adaptation based on the book series by Rick Riordan about a schoolboy who is in fact the son of the Greek god of the sea, Poseidon. The film took $14.6 million.

Last week's number one, the Denzel Washington-Mark Wahlberg action comedy "2 Guns" earned $11.1 million this weekend.

Sony's animated sequel "The Smurfs 2" was in sixth spot with $9.5 million, just ahead of Hugh Jackman's comic-book based blockbuster "The Wolverine. The latest big-screen adaptation to feature the claw-fingered "X-Men" character added another $8 million in its third week on release.

In eighth place was horror film "The Conjuring", the low-budget shocker which took $6.7 million. So far the movie has earned $120.7 million in four weeks, a phenomenal return for a film which cost a relatively modest $20 million to make.

Animated children's comedy "Despicable Me 2" was ninth with $7.4 million, as another sequel "Grown Ups 2" took 10th.

Rounding out the top 12 were Woody Allen's acclaimed drama "Blue Jasmine", with $2.5 million and animated children's flick "Turbo" with $2.3 million.