NEW ORLEANS — A performer who was part of Kendrick Lamar’s Super Bowl halftime show was detained by security after waving the Sudanese flag and Palestinian flag together with the words “Sudan” and “Gaza” written on them toward the end of the performance, the NFL said.

The first rapper to headline the N.F.L.’s biggest stage solo made his Drake diss “Not Like Us” the centerpiece of his set at the expense of a larger statement.