The long-awaited new album by Adele, "25," looks set to break the modern record for first week sales, the makers of the benchmark US chart said Saturday.

Billboard, the music industry journal that publishes weekly charts, said that "25," released on Friday, appeared likely to sell at least 2.5 million copies in the United States.

"No Strings Attached" by NSYNC, the boy band starring Justin Timberlake, is the only other album that opened with sales above two million since systematic weekly tracking began in 1991.

"No Strings Attached" sold 2.4 million copies in its first week in 2000 -- a year before the launch of Apple's iTunes, which drastically changed buying habits.

In a rare move that surely boosted sales, Adele's label chose not to make "25" available through streaming, the vast-growing platforms that offer unlimited, on-demand music online.

"25" is still available for purchase digitally and sold 900,000 copies on iTunes in the United States on the first day, according to Billboard.

"25" also looked to be one of the biggest debuts ever in Adele's native Britain, where the Official Charts Company said it sold 300,000 copies on its first day.

The only album with a bigger first-day debut was "Be Here Now" by Oasis, which sold 424,000 copies in 1997 -- again, an era in which overall music sales were much higher.

"Adele truly is a once-in-a-generation artist. Her appeal spans age groups and genres, from children to teenagers, right through to mums and dads, uncles and aunties," Official Charts Company chief executive Martin Talbot said in a statement.

The music industry has placed enormous hopes in Adele with "25."

Her last album, "21" from 2011, was the top-seller in the United States for two straight years and is the biggest release in Britain so far this century.

"25" -- led by the giant hit "Hello" -- consists largely of songs of heartache and nostalgia, following the pattern of "21" which featured the tear-jerking ballad "Someone Like You."