By Mike Collett-White

LONDON (Reuters) - U.S. sales of the seventh and final Harry Potter volume hit an estimated 8.3 million in the first 24 hours, confirming its place in the history books as the fastest-selling book ever.

"Harry Potter and the Deathly Hallows" comfortably beat the previous 2005 Potter instalment, which posted U.S. sales of 6.9 million copies in the first 24 hours, according to Scholastic, its publisher in the key American market.

Thousands of Potter fans queued outside book stores in major cities around the world over the weekend to get hold of the book, which answers the questions on every reader's lips -- Who dies at the end? Does Harry survive?

In India, police said on Monday they had seized hundreds of pirated copies of "Deathly Hallows" after raiding a printing press, storage depot and private home in Bangalore.

Internet versions of the book also surfaced last week and two U.S. newspapers ran reviews before publication, but it was not enough to dampen enthusiasm for the final chapter of the boy wizard's increasingly bloody fight against the forces of evil.

Lisa Holton, president of Scholastic Trade and Book Fairs, likened the weekend excitement in the United States to hysteria that greeted the Beatles' first visit to the country.

"This weekend kids and adults alike are sitting on buses, in the park, on airplanes and in restaurants reading 'Harry Potter and the Deathly Hallows'," she said in a statement.

Sales in Britain were also breaking records, outstripping previous Harry Potter books.

Asda supermarkets sold 97 percent of their 500,000 copies within 36 hours of the book's release, twice as fast as the sixth Potter story, "Harry Potter and the Half-Blood Prince". More copies have been ordered.

A spokeswoman at Bloomsbury, Potter's British publisher, told the Observer newspaper that British sales of the final instalment could reach three million copies in the first 24 hours, up from two million in 2005.

Waterstone's bookstores sold 100,000 Potter books in two hours, while rival WH Smith sold 15 books every second across Britain on the first night of its release, topping the record set by the previous Potter instalment of 13 per second.

And online retailer Amazon.com received 2.2 million pre-orders for "Deathly Hallows", up 47 percent on book six.

Reviews of "Deathly Hallows" have been almost universally glowing, noting the darker tone of book seven in which several characters die.

"After 608 crammed pages, it's still hard to believe it really is the end of the road for Harry," said Henry Sutton, books editor for the Daily Mirror tabloid in Britain.

He believes that the epilogue at the end of book seven means there is "no possible return" for the Harry Potter saga, although not everyone agrees.

Hours after the release of "Deathly Hallows", Ladbrokes bookmakers cut their odds on an eighth Potter tale to 10/1 from 16/1, following a flurry of bets.