WARSAW, Poland (AP) _ The Organization for Security and Cooperation in Europe says it is concerned about legal steps the Polish government is taking against a reporter who alleges the defense minister has longstanding ties with Russian military agents and members of the Russian mafia.

Tomasz Piatek, an investigative reporter for the daily Gazeta Wyborcza, published his allegations about Defense Minister Antoni Macierewicz in a new book, ``Macierewicz and his Secrets.‘’

The ministry filed a complaint with military prosecutors accusing Piatek of ``using force or threats against a public official‘’ and ``public insults or humiliation of a constitutional body.‘’ If Piatek is tried and found guilty he could face up to three years in prison.

The Vienna-based OSCE called on Poland on Thursday to show ``restraint‘’ in reacting to the book ``in order to protect freedom of the media.‘’

The OSCE said that its representative on freedom of the media, Harlem Desir, wrote to the Polish Foreign Ministry saying ``authorities should not use the courts to silence the media, whose role it is to hold them to account.‘’

Ten other media freedom groups, including Reporters Without Borders and Freedom House, also wrote to Macierewicz last month urging him to drop the legal proceedings, saying, ``this latest attempt to intimidate a journalist seems to be part of a broader two-year-old offensive against freedoms in Poland.‘’

Macierewicz, a communist-era dissident, is known as one of the most anti-Russian officials in Poland‘s conservative government. For years he has promoted a theory that the Russians might have intentionally brought down the plane in which Polish President Lech Kaczynski and 95 others died in a crash in Russia in 2010. Polish and Russian investigations determined it was an accident.

Germany’s Frankfurter Allgemeine Zeitung also alleged several days ago that Macierewicz has suspicious Russian contacts in an article titled ``The other side of the Moscow hater.‘’