The beef started when Brown posted an Instagram video making fun of 21 Savage's place of birth, which was discovered this week to be in England.
"CMON FAM, STOP PLAYING WIT DA MANS DEM," Brown wrote in the description.
Savage's music is deeply associated with Atlanta, where another fellow rapper Offset is from. Savage and Offset have been close friends for years, according to TMZ. Attorneys for Savage, whose real name is She'yaa Bin Abraham-Joseph, said he has lived in the U.S. since age 7.
"Memes ain't funny lame," Offset wrote in response to Brown's video, defending his rapper friend.
But Brown did not take kindly to Offset's comment, responding to him in an expletive-laden tirade that said: "IF YOU A REAL MAN FIGHT ME."
The Associated Press contributed to this report.