Washington ? The government’s efforts to prevent terrorists from gaining access to commercial airports are still incomplete and fragmented, a congressional report says.

The Transportation Security Administration has focused on screening passengers and baggage while paying less attention to limiting access to sensitive areas, identifying gaps in security and reducing risks posed by airport workers.

“Airports remain too vulnerable to terrorist attack,” said Sen. Joe Lieberman, D-Conn., who requested Tuesday’s report from the General Accounting Office, Congress’ investigative arm. “This level of unpreparedness is unacceptable.”

Lieberman said he was especially concerned that the TSA didn’t require airport employees to be screened before entering secure areas such as runways.

About 1 million people work at about 450 U.S. commercial airports, including catering employees, refuelers, cleaning crews and baggage handlers. The TSA has made sure that nearly all of them have had their criminal histories checked against their fingerprints.

But some workers who occasionally need access to secure areas — such as construction workers — haven’t undergone the fingerprint checks, even though the law requires them to.

The GAO report recommended more comprehensive checks because those based on fingerprints have limitations. For example, a federal investigation after the 9-11 terror attacks found more than 4,200 airport workers had falsified information to get hired and to get unescorted access to secure areas. Some had passed the fingerprint-based checks.

The TSA has expanded background checks for about 100,000 airport workers to look for links to terrorism, and it is considering ways to fund additional checks for more.

But the agency is not requiring airport workers to be screened before entering restricted areas, as the law requires.