The Pentagon issued a statement saying the Iranian jet came within 16 miles of the drone Tuesday as it conducted classified surveillance over international waters.
One of the two U.S. Air Force jets escorting the drone moved to within 2 miles of the Iranian aircraft and issued a warning, the Los Angeles Times reported Thursday.
"The Iranian aircraft departed after a verbal warning," the Pentagon statement said.
"The United States communicated to the Iranians that we will continue to conduct surveillance flights over international waters consistent with long-standing practice and our commitment to the security of the region."
Initial reports said the U.S. jets dropped a flare to warn the Iranian jet, but the Pentagon later corrected that account, the Times reported.
"Updated reporting indicates that no flare was discharged," the statement said.