Pop superstar Janet Jackson has announced a temporary halt to her global tour to undergo surgery for an unspecified condition, raising fears for her health.

Jackson, 49, who has returned with an extensive global tour after several years of relative quiet, said late Thursday that doctors told her she needed an operation "soon."

"It breaks my heart to tell you that I am forced to postpone the 'Unbreakable Tour' until the spring," she said in a statement on Twitter.

"Please pray for me, my family and our entire company during this difficult time," she said, adding that she would not give further comment on her health condition.

Jackson was due to resume her tour on January 9 in Denver and has dates across the United States, Canada and Europe lined up through late June.

She did not give an exact date for resumption of her tour but promised she would reschedule all concerts and honor tickets.

Jackson began her tour on August 31 in Vancouver, playing across North American along with several dates last month in Japan.

She earlier postponed a handful of US shows to avoid strain on her voice.

Jackson in October released "Unbreakable," her first album since the death of her brother Michael in 2009.

The death of the "King of Pop" had led Janet Jackson to retreat from the public eye, although she returned with a global tour in 2011.

Jackson's 1990 "Rhythm Nation" tour is often considered a landmark in modern concert promotion, combining a lavish dance routine with socially conscious messaging.