NEW ORLEANS (AP) — A federal appeals court says a U.S. Border Patrol agent who fired his gun in Texas and fatally wounded a teenager across the Mexican border cannot be sued by the teen's family.

The 5th U.S. Circuit Court of Appeals ruled Tuesday in the case of 15-year-old Sergio Adrian Hernandez. He was killed by agent Jesus Mesa (hay-ZOOS' MAY'-sah) in 2010. The Justice Department has said Mesa was trying to stop illegal border crossings and fired after he came under a barrage of rocks.

The appeals court voted 13-2 to uphold a federal district judge's dismissal of the family's claims. The case involved questions of whether and when constitutional rights afforded American citizens extend to non-citizens outside the nation's boundaries.

The appellate court majority said the case involved issues of diplomacy and national security.