Sao Paulo, Brazil ? A United Airlines pilot was briefly detained at the international airport in Rio de Janeiro after lowering his pants during a security screening, police said Saturday.

Pilot Michael D. Slynn, 49, was asked to remove his belt and shoes as part of a routine security screening Friday afternoon. In response, Slynn laughed at security guards and lowered his pants to his ankles, said a police spokesman who was prohibited by departmental rules from giving his name.

Slynn was detained but released shortly afterward and allowed to fly back to Washington, D.C., after signing a document promising to appear before a judge the next time he is in Brazil, the spokesman said.

Federal Police Chief Rafael Andreatta was quoted by the Internet site of the Brazilian newspaper O Globo as saying the pilot “did not respect security rules and made fun of officers.”