MONTERREY, Mexico - The U.S. National Transportation Safety Board confirmed Monday that famed Mexican-American singer Jenni Rivera died in a plane crash in northern Mexico.

It is the first official confirmation of Rivera's death, although she has been widely presumed dead since the wreckage of her plane was found Sunday.

The NTSB is sending a team to assist Mexican authorities with the investigation. NTSB spokesman Keith Holloway said Mexican aviation authorities had confirmed Rivera's death to the NTSB.

A Mexican aviation official said it would take at least 10 days to have a preliminary report on the crash.

The 43-year-old singer, born in California, was on a Learjet with six other people that took off from Monterrey early Sunday after a concert there. The wreckage was found hours later in rugged territory in northern Mexico. The plane appeared to have disintegrated on impact.

Rivera was at the peak of her career as a singer in a style of Mexican music known as grupero. She was known for her soulful voice, as well as her openness about her personal troubles.

She was recently divorced from her third husband -- former Major League baseball pitcher Esteban Loaiza.

She told reporters after Saturday night's concert that she was trying to move away from her problems and "focus on the positive." She said, "I can't get caught up in the negative because that destroys you."