U.S. and South Korean negotiators apparently have narrowed their differences over the long-debated question of whether South Korean businessman Tongsun Park will return to the United States for questioning.

Park has been indicted by a federal grand jury on charges of bribing congressmen while serving as an agent of the Seoul government.

South Korean government sources have indicated that an agreement about Park may be reached next week. U.S. officials, however, say only that "some progress has been made" and that they are hopeful an agreement can be reached soon. Park himself is unavailable for comment.

The two sides have been negotiating off and on for more than three months on a formula that might bring Park to the United Dtates to give testimony about the congressional bribery scandal.

The exact terms of the proposed agreement have not been made public, but South Korean government sources this week outlined the general terms for the press in Seoul.

Under those terms, Park would be interviewed first by U.S. officials at the American embassy with South Korean officials looking on. The main purpose of that meeting would be to determine whether Park is willing to testify before a U.S. court.

He would then be questioned on his alleged attempt to influence Congress during a second session in the office of the South Korean public prosecutor.

At a later date he would appear in a U.S. courtroom. South Korea is said to be insisting that he be granted immunity.

No timetable for the meetings has been published, but according to one report the initial questioning at the U.S. embassy would not take place before next month.

Park's testimony is wanted on a wide variety of questions about his alleged offers of money and favors to congressmen in an attempt to influence their attitudes toward his country. He would also be questioned on whether he was acting as a government agent in those dealings. South Korea's official position is that it had not authorized any of the influence-buying schemes exposed so fat.

Park returned to Seoul from London in late August, shortly before his indictment was revealed in Washington, and has refused on several occasions to go to the United States for questioning. The United States has no extradition treaty with South Korea and Seoul has said it would not force him to leave the country against his will.

The stalemate went on for weeks and a visit to Seoul by U.S. Assistant Attorney General Benjamin Civiletti failed to develop any agreement.

In late October, however, South Korean Foreign Minister Park Tong in reopened discussions with the American ambassador. Richard Sneider and since then they have held seven meetings in an attempt to reach agreement.

The new South Korean overture came at a time when the Tongsun Park case had begun to influence congressional action on military assistance for the Seoul government. The transfer of several millions of dollars in U.S. military equipment was held up in Congress because congressional leaders felt it might be rejected out of anger over the Park case.

The government of President Park Chung Hee also was under pressure from some groups that felt he had let the Tongsun Park case get out of hand to the point that it endangered national security. The transfer of U.S. military equipment to the South Korean army is considered vital with American troops preparing to leave the country.