Linebacker Aldon Smith was detained by police Sunday at Los Angles International Airport, according to an eyewitness.

A Los Angeles Police Department spokesman would only confirm that an unidentified male had been arrested and was being transported to booking, after which time his name would be released.

Smith, 24, was at Gate 6 of Terminal 1 when confronted by several police, who then led Smith away from the Southwest gate, according to eyewitness John Egan of Austin.

“I heard him say, ‘I did nothing wrong,’ ” Egans said. “The whole thing ratcheted up from there. The cops were trying to calm him down. He wasn’t out of control; just agitated.”

Smith has had multiple run-ins with police since joining the 49ers in 2011 and becoming one of the franchise’s all-time best pass rushers.

Last September, Smith was arrested for suspicion of driving under the influence following a single-car accident in San Jose, two days before a game against the Indianapolis Colts. Smith played in that game and then went on a five-week voluntary leave to attend a substance-abuse treatment facility.

Smith is also facing three felony counts of possessing illegal assault rifles, which deputies discovered after a June 2012 party at Smith’s San Jose home. Smith sustained stab wounds at the party, and two partygoers were wounded by gunfire from alleged gang members.