The defense ministry called Tuesday for stern punishment for an Army officer indicted over his Twitter posting critical of President Lee Myung-bak, saying the act of criticizing the supreme commander of the armed forces impedes military order and discipline.

Military prosecutors have put the 29-year-old captain on trial recently on charges of insulting a superior in connection with his Twitter posting criticizing President Lee with indecent language.

The indictment was seen by some critics as restricting freedom of expression.

But defense ministry spokesman Kim Min-seok said the officer deserves stern punishment.

"It is an act of impeding basic military order and discipline for a soldier to criticize the supreme commander of the armed forces. This is a case that deserves punishment of course," Kim told reporters. Superiors not only mean immediate ones, but also cover the highest level in the chain of command, he said.

"The military court will proceed with a trial according to law and procedures," Kim said.

Kim said the ministry also plans to deal sternly with any soldiers on active duty if they are found to be members of the minor opposition Unified Progressive Party. By law, soldiers are banned from being members of a political party.

Prosecutors seized the list of UPP members during a recent raid carried out as part of an investigation into alleged irregularities in the party's voting to select proportional representation candidates for last month's parliamentary elections.

"Soldiers on active service cannot join a political party," Kim said. "If there are any active-duty soldiers on the list and if the prosecution hands the list over to us, we will make a stern judgment according to the law." (Yonhap News)