NEWARK, N.J. (AP) _ A Taiwanese man charged with conspiring with a high-level U.N. diplomat to export arms to China has pleaded guilty in the case, court records obtained Wednesday show.

Shang-Yao Chi, 65, of New York City entered the plea at an unannounced hearing last Thursday in federal court, according to the records.

Minutes of the hearing, filed with the clerk's office, gave no further details of the plea. Sentencing was set for Feb. 8.

At the hearing, U.S. District Judge Dickinson R. Debevoise approved a defense request to seal all records of the case. It was unclear why some of the documents were in the public file in the court clerk's office.

Chi was arrested in Jersey City on Sept. 27 in a Customs Service undercover operation. He initially pleaded innocent Oct. 21.

The government alleged that Chi sought to export to China 10 TOW II missiles, a powerful anti-tank weapon, and also had other weapons on a ''shopping list'' for future consideration. No arms shipments were ever made.

One of two unindicted co-conspirators named in the indictment was described as an official of the Chinese mission to the United Nations. Such officials generally have diplomatic immunity from prosecution.

Customs agent Frank Ventura and officials in the U.S. attorney's office identified the diplomat as Fan Lianfeng, a high-ranking member of the mission's military delegation. They said he left the country after the case broke.

The Chinese U.N. mission has denied any involvement in the plot. A spokesman, Yuan Zhang, did not return telephone calls Wednesday.

Assistant U.S. Attorney Samuel P. Moulthrop on Wednesday said he would not discuss the case until the record was unsealed, and wouldn't specify when that might happen.

Chi's attorney, Alan Zegas, also said he would speak freely when the order was lifted.

Authorities said a New York man, Charles Chang, was arrested first in the case, after he negotiated with a Customs agent posing as an arms dealer.

Chang then agreed to tape-record conversations with Chi without Chi's knowledge, and has since pleaded guilty in the case. He was the other unindicted co-conspirator named in the indictment.

The alleged ''shopping list'' included blueprints for the F-14 fighter jet, which the United States has never sold to China, and Sidewinder missiles, authorities said.

Chi was charged with conspiracy to export defense items without authorization. The charge carries a penalty of five years in prison and a $250,000 fine.

Chi was being held without bail at the Metropolitan Correctional Center in New York.