Attorneys for accused spy Larry Wu-Tai Chin have asked a federal judge to block prosecutors from using statements Chin made to FBI agents the night of his arrest, contending that the agents violated Chin's constitutional rights while questioning him.

In one of several motions filed in federal court in Alexandria Thursday, Chin's lawyers, Jacob Stein and Gary Kohlman, said Chin "clearly asserted his desire to receive the assistance of counsel and was affirmatively frustrated in that effort by the investigating agents."

They also argued that Chin, 63, a retired analyst and translator for the CIA, was not adequately advised of his rights and that, even if he had been, "his physical and psychological circumstances" prevented him from freely exercising them.

As a result, the lawyers said, Chin's statements "at the time of his arrest" Nov. 22 or after the arrest should be suppressed.

FBI agent Mark R. Johnson testified at a court hearing last month that an FBI affidavit supporting Chin's arrest was "principally based" on agents' "conversation" with Chin for more than five hours before his arrest. During that interview, Johnson said, Chin admitted spying for China.

It was not clear from the motion whether Chin's lawyers would attempt to block the use of those statements, which were made before Chin was formally arrested.

The motion did not detail in what way the FBI allegedly violated Chin's rights. At the hearing last month, a lawyer for Chin argued that agents "grilled him over an entire evening without allowing him to seek counsel." At one point, the lawyer said, Chin asked one of the agents, who is a lawyer, if he would serve as his attorney.

In other motions, the lawyers also asked U.S. District Court Judge Albert V. Bryan Jr. to block the use of evidence agents seized from Chin's Alexandria home the next day on the grounds that the search warrant was invalid and that agents lacked probable cause to conduct the search.

They also asked Bryan to order prosecutors to disclose whether agents had tapped Chin's phone, opened his mail or used "any other form of surreptitious activity."

A hearing on the motions is set for Jan. 3, and Chin's trial is scheduled to start Jan. 22.