A San Francisco man claims he was high on a double dose of medical marijuana cookies when he screamed, dropped his pants and attacked crew members on a cross-country flight, forcing its diversion to Pittsburgh, the FBI said Wednesday.

Kinman Chan, 30, was charged in a criminal complaint with interfering with the duties of a flight attendant on allegations that he fought with crew members of US Airways Flight 1447 from Philadelphia to Los Angeles on Sunday. His federal public defender, Jay Finkelstein, declined to comment.

Crew members said Chan made odd gestures before he entered the plane's rear restroom shortly after takeoff and began to scream, according to the complaint.

Chan told the FBI that he "came back to reality" and exited the restroom, at which point the crew noticed his "pants were down, his shirt was untucked and all the compartments in the restroom were opened."

When crew members tried to get Chan to sit, he fought them and had to be subdued in a choke hold, the complaint said.

Chan told agents who interviewed him in Pittsburgh that he ate marijuana cookies while waiting for his flight to depart in Philadelphia.

Margaret Philbin, a spokeswoman for the U.S. attorney's office in Pittsburgh, said Chan has a legally issued medical marijuana card for a "legitimate" health issue, which she declined to identify.

Chan was arrested in Pittsburgh, then jailed until a federal magistrate granted him bond Tuesday, Philbin said.

Chan remained jailed Wednesday because Allegheny County officials have also charged him with disorderly conduct, Philbin said.

The charge of interfering with the duties of a flight attendant carries up to 20 years in prison and a $250,000 fine.