NEW YORK - There's clearly something about Harry.

The new Harry Potter book sold an astonishing 6.9 million copies in its first 24 hours - averaging better than 250,000 sales per hour and smashing the record held by the previous Potter release.

"This is a cause for celebration, not just for Scholastic, but for book lovers everywhere," said Lisa Holton, president of Scholastic Children's Books, author J.K. Rowling's U.S. publisher.

Sales for the sixth installment of Rowling's fantasy series easily outpaced those for Potter V, "Harry Potter and the Order of the Phoenix," which came out in 2003 and sold 5 million copies in the first 24 hours.

Acknowledging that some stores quickly ran out of books two years ago, Scholastic has already increased the print run for the latest "Harry Potter and the Half-Blood Prince" from 10.8 million copies to 13.5 million.

The Scholastic numbers are for the United States only. Sales figures from Britain are expected today.

Anticipated from the moment fans finished Potter V, the new book has been available virtually everywhere, from price clubs and supermarkets to the Scholastic Web site. Holton said Sunday that a big factor in the new sales record was a six-fold increase in the number of Potter bookstore parties, from 800 to 5,000, with both superstores and independent retailers dramatically increasing their participation.

Even allowing for deep discounts on the $29.99 release, "Half-Blood Prince" still easily generated more than $100 million in revenue. It's not only the richest opening in publishing history, but tops the combined estimated take for the weekend's top two movies, "Charlie and the Chocolate Factory" and "The Wedding Crashers."

"When a book beats out movies, we're in great shape," Holton said.

Meanwhile, Barnes & Noble Inc. estimated 1.3 million U.S. sales for the latest Potter book in its first 48 hours, around 400,000 higher than for the first 48 hours of Potter V. Rival superstore chain Borders Group Inc. reported a record 850,000 Potter sales worldwide in the first day, 100,000 greater than for the debut of "Order of the Phoenix."

Although the book only went on sale midnight Saturday, some have already decided to pass their copies on to others. Used editions were available through eBay, Amazon.com and Alibris.com.