Authorities would not describe the condition of the remains but said they do not know how many people they belong to.
The remains were found Tuesday at the site of the wreckage and were transported to Monterrey, the same city the private Learjet took off from, said Priscila Rivas, spokeswoman for the state's public ministry.
It is too early to tell if Rivera's remains were among those found, Rivas said, but DNA tests are under way. Test results could take anywhere from a day to weeks, she said.
Rivera's brother, Lupillo, arrived in Monterrey Tuesday from the family's home in Lakewood, California. Before he left California, he described the situation as "95% bad news" but added that the family is clinging to the small hope that Jenni Rivera somehow survived.
A makeshift altar with flowers, balloons and candles appeared on the family's front lawn.
"I trust in God, and he gives me strength," said Rivera's mother, Rosa Rivera. "I know that if indeed (she's dead), I would thank God for the time he shared her with me, for the precious time she called me Mother."
Six others, including two pilots, were thought to be on board the plane, which lost contact with air traffic controllers soon after takeoff.
Born in Long Beach, California, to Mexican immigrant parents, Rivera, 43, released her debut album in 1999, according to her website.
In October, People en Espanol named Rivera to its list of the 25 most powerful women.
Famous for her music, she is also known for her tumultuous personal life. The singer was a single mom at the age of 15, is thrice-married and the mother of five, her website said.
Rivera's "I Love Jenni" reality show began airing on Telemundo's mun2 network last year.
She is a judge on the popular TV show "The Voice Mexico," which was scheduled to air Sunday night on Televisa. Noting its concern for Rivera, Televisa said it would air a special report on the singer instead.
"To all her fans who are suffering, I say thank you, and don't suffer. Soon we will have news of her," Rosa Rivera said.