Pixar's animated monsters have beaten Brad Pitt's zombies to the top of the U.S. box office, scaring up almost $150 million (£97 million) between them.

Monsters, Inc. prequel Monsters University has rocketed to number one with an $82 million (£53 million) opening-weekend take, while apocalyptic thriller World War Z comes in second with $66 million (£43 million).

Last week's top movie, Man of Steel, is third with a $41.2 million (£27 million) second-weekend haul.