has leaked online three weeks ahead of its US release.
The online copy of the film has been downloaded through piracy sites more than 189,000 times over a 24-hour period, reported Variety.
Lionsgate, which is distributing the movie, declined to comment. The original source of the pirated copy is unclear and user comments posted on piracy websites indicate the rip is genuine.
Pirated copies of the film cropped up on torrent-sharing sites on Wednesday July 23 and downloads started to spike Thursday, according to data provided by piracy-analytics firm Excipio.
The Expendables 3 ensemble cast includes Jason Statham, Antonio Banderas, Jet Li, Arnold Schwarzenegger, Dolph Lundgren, Kelsey Grammar, Terry Crews, Mel Gibson, Wesley Snipes and Harrison Ford.
A similar leak happened in 2009, when a rough cut of 20th Century Fox's X-Men Origins: Wolverine was shared on Megaupload.com about a month before the its premiere.
Fox estimated that at least 15 million people downloaded the movie, and represented tens of millions of dollars in lost revenue.