WASHINGTON ÷ Fake guns, bombs and other weapons got past security screeners almost one-fourth of the time at 32 major airports last month, a Transportation Security Administration official said Monday.

At three airports ÷ Cincinnati, Las Vegas and Jacksonville, Fla. ÷ undercover testers got weapons past security at least half the time, the official said, speaking on condition of anonymity.

The official said the findings were incomplete and the testing period ended Monday.

In February, the Transportation Security Administration, rather than the airlines, began supervising airport checkpoints, but the screeners continue to work for private companies. Federal employees are supposed to replace them by Nov. 19.

Transportation Security Administration spokeswoman Mari K. Eder said the agency continues to test how well the screeners find weapons and explosives to help the agency improve security.

The test results were first reported Monday by USA Today.

Currently, government employees are screening passengers at only three airports ÷ Baltimore, Louisville, Ky., and Mobile, Ala. ÷ but the security agency said last week it will begin overhauling checkpoints at more than 130 other airports this month. Thatās the first step toward replacing the private screeners with an all-federal work force.

But progress toward hiring screeners may be delayed unless Congress approves a supplemental spending bill that includes some $4 billion for the agency, said Transportation Secretary Norman Y. Mineta.

In a letter to lawmakers, Mineta warned it would be "nearly impossible" to meet the Nov. 19 deadline if the money was not approved. In addition, he wrote, the security agency would have to suspend purchases of explosive detection equipment and delay reconstruction of airport checkpoints.

Office of Management and Budget spokesman Trent Duffy said the White House would transfer at least $250 million to the Transportation Security Administration until the supplemental bill passes. In May, President Bush transferred $760 million from the Federal Emergency Management Agency.

The airport tests revealed screeners found hidden simulated weapons or explosives at least 90 percent of the time in Miami, Newark, N.J., Fort Lauderdale, Fla., and Honolulu. They missed the weapons 41 percent of the time in Los Angeles.

Overall, the screeners failed to detect prohibited items 24 percent of the time.

The Transportation Departmentās inspector general office earlier conducted its own undercover tests of 32 airports after the Sept. 11 terrorist attacks and found screeners missed knives 70 percent of the time, guns 30 percent of the time and simulated explosives 60 percent of the time, said a person familiar with the report. Those tests were conducted before February, when airlines still supervised security checkpoints.