BERLIN (AFP) - Six German sailors have been charged with mutiny over accusations they tied up their superior onboard a ship, in a first for the German navy, officials said Friday.

The six allegedly pulled the petty officer from his cabin, tied him with tape to a table and wrote "the retards live here" on his lower leg, according to the public prosecutor's office in the northern town of Rostock.

The alleged incident took place onboard the Hermelin, which was part of the UN mission in south Lebanon, UNIFIL, while the boat was in the Lebanese capital, Beirut, in February.

The petty officer is of Thai descent but there is no indication the incident was racially motivated - the alleged victim had himself apparently used the term "retard" earlier to refer to non-officer crew members.

"They wanted to teach the petty officer a lesson," the public prosecutor's spokesman said.

A defence ministry spokesman told reporters that as far as he was aware, it was the first time a charge of mutiny had been brought within the German navy.

They have also been charged with aggravated battery and depriving someone of their personal freedom, according to the prosecutor's office.

On the mutiny charge alone, they face a jail term of between six months and five years.

The petty officer was not seriously hurt.