Bristol Palin and Levi Johnston split up

ANCHORAGE, Alaska, March 11 (UPI) -- The 18-year-old daughter of former U.S. vice presidential candidate Sarah Palin has broken up with the father of her 2-month-old son, People.com said.

Bristol Palin, the daughter of the Republican governor of Alaska, and her fiance, Levi Johnston, ended their relationship a few weeks ago, a source said without offering details about what led to the split.

"It was a mutual thing," the insider told People.com. "It kind of just happened ... . I thought they would stick it out. But I think they can work together to raise Tripp."

"I'm not sure what caused (them to break up) -- it's common knowledge," another source who knows the family told the magazine.