As of 4 p.m. Thursday, cellphone users in at least a dozen cities -- Los Angeles, Rancho Cucamonga, New York, Atlanta, Charlotte, Raleigh, Houston, Huntsville, Texas, Norfolk, Virginia, and Tuscaloosa, Alabama -- reported receiving the messages.
"We wanted to inform you about a recent incident involving a post on social media which included racially motivated language," Eric Cypher, principal at Los Osos High School in Rancho Cucamonga, said in a statement. "This message was then sent to a few students through a text message. After further investigation, we have found that this message is part of a larger, nationwide trend of disruptive content being shared.
"We are in communication with local law enforcement to monitor these situations and ensure our school remains a safe and positive environment," Cyhper said. "As a campus and community, we will not tolerate the use of racial slurs and culturally insensitive language."
The messages, sent anonymously, generally used a similar tone but varied in wording.
Nicole Nuñez, whose 15-year-old son attends a Stella Charter School in Los Angeles, said her son and some of his friends also got a similar text message.
"It said he has been chosen to be part of group B to go pick cotton at a plantation, and he will be picked up by a black van and to be ready by 6pm. And he said a lot of his Hispanic friends have also gotten the message saying that they will be deported, so they're getting different messages just worded a little differently," said Nuñez.
She said her daughter also got a threatening text that said if she refused, she would be taken by force and her brother would be executed.
"My question I have is, how do they know my son's name? How is all this information being sent out to minorities with our specific names? That's very scary," said Nuñez.
Some instructed the recipient to show up at an address at a particular time "with your belongings," while others didn't include a location. Some of them mentioned the incoming presidential administration.
It wasn't yet clear who was behind the messages and there was no comprehensive list of where they were sent, but high school and college students were among the recipients.
The FBI said in a statement that it is "aware" of the suspicious messages and "is in contact with the Justice Department and other federal authorities on the matter."
"As always, we encourage members of the public to report threats of physical violence to local law enforcement authorities," the agency said.
A spokesperson for the Federal Communications Commission said in a statement, "Our Enforcement Bureau is aware of these and is looking into them alongside federal and state law enforcement."
Civil rights organization NAACP condemned the messages, saying they will fight against letting hateful rhetoric be "normalized."
"These messages represent an alarming increase in vile and abhorrent rhetoric from racist groups across the country, who now feel emboldened to spread hate and stoke the flames of fear that many of us are feeling after Tuesday's election results," the organization said.
Racist text messages referencing slavery raise alarms in multiple states and prompt investigations
Tasha Dunham of Lodi, California, said her 16-year-old daughter showed her one of the messages Wednesday evening before her basketball practice.
The text not only used her daughter's name, but it directed her to report to a "plantation" in North Carolina, where Dunham said they've never lived. When they looked up the address, it was the location of a museum.
"It was very disturbing," Dunham said. "Everybody's just trying to figure out what does this all mean for me? So, I definitely had a lot of fear and concern."
Her daughter initially thought it was a prank, but emotions are high following Tuesday's presidential election. Dunham and her family thought it could be more nefarious and reported it to local law enforcement.
"I wasn't in slavery. My mother wasn't in slavery. But we're a couple of generations away. So, when you think about how brutal and awful slavery was for our people, it's awful and concerning," Dunham said.
"I don't understand why there's so much hate in this world, I don't understand why they don't like us, because of the color of our skin," said Nuñez.
ABC News contributed to this report.