WASHINGTON (AP) _ Congressional hearings into how the White House obtained more than 400 FBI background files should be put on ``a fast track right away,'' Senate Majority Leader Trent Lott said Sunday.

``I think we should have a hearing by the appropriate committee, Judiciary or Government Affairs, quickly and clear this up and move on _ if it can be cleared up quickly,'' Lott said on CBS' ``Face The Nation.'' ``Maybe there's just more to it than we now realize.''

At issue is another political embarrassment for the White House _ how the Clinton administration came into possession of more than 400 FBI background files on current and former White House aides. Included on the list are some prominent Reagan and Bush aides, including former Secretary of State James A. Baker III.

President Clinton, who has taken responsibility for the files flap, has called it an honest case of bureaucratic bungling, a conclusion with which Lott was unwilling to concur.

``Again, it is part of a pattern of things being done, or files or papers being where they shouldn't have been, and everyone saying, `Gee, I didn't know that,''' Lott said. ``There legitimately should be hearings on it.''

Also, The Washington Post reported Sunday that Secret Service officials have told Senate Republicans that their White House access list _ the one the Clinton administration has claimed was outdated _ in fact has been updated at least once a month since Clinton took office.

Three GOP senators said in a letter to the chairmen of the House and Senate panels overseeing White House matters that the Secret Service has informed them that its list is constantly updated, usually twice or three times a week. The White House has claimed that it came into possession of the GOP files because the Secret Service list of those with access to the executive mansion was woefully outdated.

Lott set no specific timetable for Senate hearings. But Rep. William Clinger, R-Pa., said he will hold the first of perhaps three hearings on the matter this Wednesday in the House Government Reform and Oversight Committee, which he chairs.

``There may be more there _ this has been sort of an evolving situation,'' Clinger said on ``Fox News Sunday''. ``This really does raise enormous questions of privacy.''

``I can't conceive of any explanation for these files being requested,'' Sen. Mitch McConnell, R-Ky., said on the same program. ``Until we have comprehensive public hearings, there is no way to know what might have been the motive.''

McConnell added that he believes sworn testimony from White House officials will be needed ``to get a handle on what was really going on.''

``There's every indication,'' McConnell added, ``that this administration ... was requesting and possibly rifling through FBI files.''

The White House has insisted the files were inadvertently obtained as administration security officials tried in 1993 to bring up-to-date their list of who had access to the White House.

White House spokesman Mark Fabiani argued, however, that the White House has been forthcoming about how it came into possession of the files _ and that there is no evidence any of them had been reviewed.

``Every fact that has emerged so far...is that this is an innocent mistake,'' Fabiani said. ``It was a big mistake, it was a huge mistake _ that doesn't make it right. But most of these were names that not anyone would recognize.''