WASHINGTON (AP) _ The U.S. official responsible for Y2K readiness said Sunday he is confident there will be no catastrophic computer breakdowns but is concerned public reaction to any small problems could provoke economic crises.

``If we got a panic we could ... create a shortage of all sorts of things as we go forward _ either food, gas, pharmaceuticals,'' John Koskinen, the White House Y2K coordinator, said on CNN's ``Late Edition.''

Koskinen said there were no signs so far that Americans were concerned enough by the hype surrounding the millennium bug that they were beginning to hoard supplies or remove large sums from their bank accounts.

``Our biggest concern is that we may have a whole series of otherwise manageable events one at a time but, particularly internationally, there may be a number of them,'' Koskinen said. ``We may be monitoring and responding to more difficulties than you would normally have to deal with. And I think that's probably our worst-case scenario.''

Koskinen also noted that potential glitches may not present themselves at midnight on Dec. 31 but could take several days or a week to become evident.

``If they have a problem internationally, it'll be a slow degradation of service,'' he said.