Los Angeles - Sci-fi sequel Dawn of the Planet of the Apes beat a horror flick, an animated family film and an adult comedy to keep its grip on the US and Canadian box office title for a second straight weekend.
Apes collected $36m in domestic ticket sales from Friday through Sunday, according to estimates from Rentrak. Low-budget horror film The Purge: Anarchy finished in second place with $28.4m.
Another new nationwide release, Walt Disney's animated Planes: Fire and Rescue, grabbed $18m to take third place, while comedy Sex Tape took in $15m for the No 4 spot.
Apes, a sequel to 2011 franchise reboot Rise of the Planet of the Apes, stars Andy Serkis as Caesar, a brainy ape who leads the interaction with humans in a battle for dominance.
The Purge: Anarchy, produced for $9m, is a follow-up to 2013 summer horror hit The Purge. The film tells the story of a couple whose car breaks down at the beginning of the purge, a 12-hour period in which crime is legal.
Another sequel, Planes: Fire and Rescue, features the voice of US comedian and actor Dane Cook as a crop dusting plane that joins forces with a team of rescue vehicles to fight a wildfire.
Sex Tape stars Cameron Diaz and Jason Segel as a married couple who accidentally upload a racy video of themselves onto the internet.
Dawn of the Planet of the Apes was released by 20th Century Fox, a unit of Twenty-First Century Fox. Sex Tape was distributed by Sony's movie studio. The Purge: Anarchy was released by Universal Pictures, a unit of Comcast.