Prosecutors demanded an 18-month prison term Wednesday for a man charged with defacing a public lavatory in Suginami Ward, Tokyo, with antiwar graffiti in April.

"Graffiti is becoming a social problem and there is growing public demand for serious punishment in such cases," a prosecutor told the Tokyo District Court.

Lawyers for the 25-year-old defendant, a bookstore employee whose name was not provided, argued that the indictment was politically motivated and designed to suppress public opposition to Japan's support for the U.S.-led invasion of Iraq this year.

"It's unfair to charge (the defendant) with damaging a building," lawyer Shoji Nishimura said. "It would be proper in this case to charge him with violation of the Minor Offense Law or the Suginami Ward ordinance banning the drawing of graffiti."

Damaging a building is a criminal offense that carries punishment of up to five years in prison. People punished under the Minor Offense Law can be fined a maximum of 10,000 yen or detained for up to 30 days. The ward ordinance carries a fine of up to 20,000 yen.