NEW YORK (AP) _ Hundreds of Patriot missiles in the Mideast and South Korea had to be quickly replaced by the Army after tests found potential flaws in the weapons system, The Wall Street Journal reported today.

``A significant number of failures were found'' during testing and the decision was made to replace all ``suspect missiles,'' said Lt. Gen. Paul Kern, a top acquisition officer for the Army.

The number of withdrawn missiles remains classified, but the missiles were pulled over the past 10 days from approximately 11 batteries protecting U.S. forces in South Korea, Kuwait and Saudi Arabia, the newspaper reported.

A typical battery has about 64 missiles, and unidentified officials told the Journal that the number pulled was certainly in the hundreds.

The part of the system that appears most vulnerable is a radio frequency downlink that allows the missile to communicate with radar guiding its flight, the Journal reported.

U.S. allies, which also rely on the Patriot system, have been informed of the problem. The issue is of particular concern to Israel, which, like the United States, tends to keep more of its Patriot launchers on full alert, the Journal said.

Kern said engineers were working on the problem, but he did not know how long it would take to find a solution. Dave Shea, a spokesman for Raytheon Co., the missile manufacturer, said the company is working with the Army to identify and resolve the problem.