A former top-level State Department official illegally took a secret, unauthorized trip to Taiwan (search) last year and met with Taiwanese intelligence officers, according to a criminal complaint.

Donald W. Keyser (search), a 30-year veteran at the State Department (search), was charged Wednesday with deliberately concealing from his superiors that he took a four-day trip to Taiwan last September. Federal law requires an individual with Keyser's security clearances to report all foreign travel.

Keyser would not have been permitted to travel to Taiwan on official business because the United States and Taiwan do not have formal diplomatic relations, according to court papers.

Keyser's attorney, Robert Litt, was unavailable for comment Thursday, and a phone call to Keyser's home was not immediately returned. At a court appearance Wednesday, Keyser was released on a $500,000 bond and a preliminary hearing was set for Oct. 13.

The State Department declined comment on the case Thursday because it involves an ongoing investigation.

According to a criminal complaint submitted by the FBI, Keyser admitted meeting with a Taiwanese intelligence officer on the trip last year, but said he had only flown to Taipei "for sight-seeing purposes."

FBI agents monitoring Keyser's activity in recent months found that he frequently met two Taiwanese intelligence officers, including the officer he met in Taiwan, at Washington-area restaurants, where they would exchange papers.

FBI agents stopped the two Taiwanese officials after a Sept. 4 lunch meeting in Alexandria, and found one of the officers carrying a six-page document titled "Discussion Topics." State Department analysts who reviewed the document said some of its contents were derived from material to which Keyser had access while at the State Department, according to the complaint.

The FBI complaint provided no details about the contents.

The charges against Keyser make no allegations of espionage, and nothing in the complaint indicates that Keyser passed on classified material to the Taiwanese officials.

Keyser retired from the department in July after rising to the post of principal deputy assistant secretary for East Asian and Pacific Affairs.

In 2000, he was disciplined and reassigned by then-Secretary of State Madeleine Albright as part of an investigation into a missing laptop computer that contained classified information.