Science-fiction action film Riddick, starring Vin Diesel as the title character, soared to the top of the domestic box office this weekend. The third movie in the Chronicles of Riddick series, Riddick, distributed by Comcast (CMCSA 1.02%) subsidiary Universal, pulled in more than $18.6 million at the domestic box office in its opening weekend, according to data and statistics compilation firm Rentrak.

Riddick also scored the top worldwide spot at the box office, with its international haul bringing its total weekend revenue to more than $26 million in all. With a reported production budget of $38 million, according to Box Office Mojo, Riddick looks well on its way to emerging as a financial success for Universal and Comcast.

Lee Daniels' The Butler dropped to the No. 2 slot at the domestic box office, taking in $8.9 million over the weekend and bringing its total gross to nearly $92 million. The film, which stars Forest Whitaker and Oprah Winfrey and tells the story of a White House butler, has not been released internationally. The Spanish-language comedy Instructions Not Included earned third place at the domestic box office in its expanded second weekend with $8.1 million, giving it a total of $20.1 million in U.S. and Canadian theaters.

Science fiction thriller Elysium, distributed by Sony (SONY -1.11%), ran in second place at the worldwide box office over the weekend. Despite waning domestic sales, Elysium scored internationally, pulling in more than $21 million abroad as part of a $24.3 million weekend in all. Cumulatively, Elysium has sold more than $212 million during its box office run. Box Office Mojo puts its production budget at $115 million.

Comedy film We're the Millers continued its successful run at the box office this weekend, ranking in third worldwide and fourth domestically with more than $17.8 million in sales. The film, distributed by Time Warner (TWX) subsidiary Warner Brothers, has recorded more than $178 million worldwide during its box office run, with more than $123 million of that total coming domestically.

With a reported production budget of just $37 million, We're the Millers, starring Jason Sudeikis and Jennifer Aniston, has emerged as one of the box office's under-the-radar successes for Time Warner late in the summer season.

-- Material from The Associated Press was used in this report.