NEW YORK - Madonna has released six new songs months ahead of schedule, furious that early versions had been leaked online in what she described as "artistic rape".
The songs will appear on the pop icon's first album in three years, Rebel Heart, which comes out in March.
The six tracks released on Saturday show Madonna going further in a hip-hop direction, and include a collaboration with leading female rapper Nicki Minaj.
The Material Girl said that she decided to put the songs on sale online after in-studio versions of her tracks were leaked on the Internet.
"I would prefer my fans to hear completed versions of some of the songs instead of the incomplete tracks that are circulating. Please consider these six songs an early Christmas gift," she said in a statement.
Madonna earlier took a more livid tone on social media. On Instagram, she called the distribution of her unfinished songs "artistic rape" and "a form of terrorism" against the creative process.
She deleted the message, but in a series of further postings - including one accompanied by a scantily clad photo of herself off the Internet, which she said had not been intended for release - she asked for leads to figure out how her demos got out.
The leaks came as entertainment giant Sony suffered a major hacking incident, linked by United States investigators to North Koreans upset over mockery of their leader in the since-cancelled film The Interview. But the leaks of Madonna's music are unlikely to be connected as she is distributed by rival music group Universal.
Leaks have become an increasingly common problem for artists in an age where copying music takes little technical skill. Last year, Lady Gaga also released music early after leaks, while Beyonce avoided the problem by releasing an album with no prior publicity.
The new songs see Madonna - creator of some of the most recognisable dance pop songs of the 1980s - going further into an R&B style, which she had touched on as far back as 1989's Like A Prayer and embraced on her 2008 album Hard Candy.
The songs come after what had been a quiet year for Madonna, who dropped off Forbes' annual list of the highest-earning female musicians after topping it a year earlier.
Madonna has yet to announce concert plans. Her 12th album MDNA was accompanied by an extensive global tour that grossed more than US$300 million (S$394 million), and generated controversy as she raised issues from gun control to gay rights and Europe's far right.