TOKYO - Weeks after three Americans detained in North Korea were released, a U.S. citizen has shown up in the repressive state, appearing on television to denounce his home country as a "mafia enterprise" and call American democracy "an illusion."

Although details remain sketchy, it seems that the man, Arturo Pierre Martinez, 29, of El Paso, Texas, willingly went to North Korea. He says he is not being detained.

At a news conference Sunday in Pyongyang, Martinez criticized the U.S. for alleged human-rights violations.

"The illegal war carried out against the nation of Iraq serves as a perfect example of how the U.S. government acts much like a mafia enterprise by criminally plundering entire nations of their resources, strategic reserves, and economies instead of smaller-scale business and individuals, and does so without a code of ethics," he said in a video released by the official Korean Central News Agency.

But his mother, Patricia Eugenia Martinez, told CNN that her son has bipolar disorder and had previously tried to enter North Korea by swimming across a river but was apprehended and sent back to the United States, where he was treated at a psychiatric hospital in California.

North Korea said in a statement that Martinez entered the country last month, just two days after James R. Clapper Jr., the top U.S. intelligence official, went to Pyongyang to secure the release of Kenneth Bae and Matthew Todd Miller, two Americans who were being held by North Korea. Another American, Jeffrey Fowle, was released in October after six months in detention.

State Department deputy spokeswoman Marie Harf said, "We are aware of reports that a U.S. citizen crossed into North Korea, and we stand ready to provide all consular assistance," the Associated Press reported. She did not provide any additional information, citing "privacy considerations."