A 36-minute clip of the latest Harry Potter movie Harry Potter and the Deathly Hallows: Part I (2010) has been leaked online ahead of its international release.

Warner Bros said it was "working actively" to remove the video, which it said was "stolen and illegally posted" on file-sharing websites on Tuesday.

"We are vigorously investigating this matter and will prosecute those involved to the full extent of the law," it added in a statement.

Harry Potter and the Deathly Hallows Part 1 opens in the UK on Friday.

It is one of two films to be adapted from the final book in JK Rowling's best-selling series.

It is not yet known how the first 36 minutes of Deathly Hallows Part 1 came to be posted online.

A studio spokesman said its distribution "constitutes a serious breach of copyright violation and theft of Warner Bros property".

"We are working actively to restrict and/or remove copies that may be available," its statement added.

Deathly Hallows Part 1 could have the biggest opening weekend so far for the fantasy film franchise, according to industry experts.

They believe it could pass the $100 million (£62.7m) mark in North America in its first three days and take more than $1 billion (£627.5m) in global ticket sales.

According to the Box Office Mojo website, the first six Harry Potter films have earned $5.4bn (£3.4bn) at the worldwide box office.

Harry Potter and the Deathly Hallows Part 2 will be released next summer.

Source: Press Release