The Transportation Security Administration has imposed a hiring freeze in the midst of its effort to meet fast-approaching congressionally imposed deadlines to check all passengers and baggage at commercial airports.

Congress capped TSA at 45,000 full-time employees when it created the agency in response to the Sept. 11 attacks. The agency will have close to that number by this weekend, when a new batch of screeners comes on board, TSA spokesman Robert Johnson said Thursday.

TSA chief James Loy imposed the freeze Wednesday night.

"It's premature to say whether we will or will not be able to meet our deadlines," Johnson said. "We're going to keep working with Congress."

The TSA has said it would need up to 67,000 employees, a figure that House Republicans, in particular, have said is too high.

Rep. Hal Rogers, R-Ky., chairman of the House Appropriations transportation subcommittee, harshly criticized the TSA at a hearing of the full committee Thursday.

"They are growing too fast into a huge bureaucracy," he said. "We have reviewed TSA's staffing estimates and concluded that they can do the job with 45,000 full-time federal employees."

The TSA has asked Congress for $5.4 billion next year, but Rogers said House Republicans want to trim that by $200 million and rearrange spending. The GOP plan calls for more to be spent on such things as airport modifications to accommodate bomb-detection machines and to speed up installation of stronger cockpit doors -- and less on staffing.

Congress gave TSA until Nov. 19 to take over the responsibility of screening passengers from private companies, an effort the agency says will take about 30,000 people.

The TSA also was given a Dec. 31 deadline to hire people to screen all commercial air travelers' baggage for explosives. That will require an estimated 21,600 people, according to TSA.

George Naccara, TSA's security director at Logan International Airport, said he still needs to hire 300 to 400 more passenger screeners to meet the deadline. If the hiring freeze lasts more than a week or 10 days, "it could become a problem for us," he said.

The government's fiscal year ends Monday. Congress is expected to pass a bill keeping agencies open for the first week of the fiscal year by extending previous budget authorizations.