LOS ANGELES (AP) - Michael Moore's attorney said in New York on Monday that the filmmaker's criticism of the Bush administration may have prompted a federal investigation into his trip to Cuba for the upcoming health care documentary, "Sicko."

In a letter to the U.S. Department of the Treasury's Office of Foreign Assets Control, attorney David Boies noted that Moore has been a critic of President Bush in his books and films, which include 2004's "Fahrenheit 9/11," a harsh indictment of White House actions regarding the Sept. 11 attacks.

"For this reason, I am concerned that Mr. Moore has been selected for discriminatory treatment by your office," Boies wrote in response to a letter sent to Moore last month from Dale Thompson, OFAC chief of general investigations and field operations.

The OFAC letter notified Moore that he was under investigation for possible violations of the U.S. trade embargo restricting travel to Cuba.

A copy of Boies' letter was obtained by The Associated Press before an afternoon news conference at the attorney's New York office by Moore, Boies and Harvey Weinstein, co-chairman of the Weinstein Co., which is releasing "Sicko" on June 29.

"I am requesting that you provide to me information regarding the person or persons who participated in making the decision to send Mr. Thompson's letter, the nature of the discussions that took place and the knowledge your office had of Mr. Moore and his trip to Cuba at the time the letter was sent," Boies wrote.

Moore went to Cuba in March to obtain health care for three ailing Sept. 11 rescue workers. He claims in the film that the U.S. government had left the workers to fend for themselves on ailments that resulted from their work at ground zero.

Last fall, Moore asked the Department of the Treasury for permission to go to Cuba under U.S. rules permitting travel there by journalists. OFAC's letter noted that Moore went to Cuba without having gotten any response from the office.