Undercover investigators¹ managed to smuggle² bomb-making materials into key US government buildings on 10 occasions last year, a congressional report says.

国会报告称，秘密调查者已经成功查出去年10次政府建筑爆炸案的炸弹组成材料。

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Senator Joe Lieberman has called the security lapses \"simply unacceptable\"

The Government Accountability Office said that once inside the buildings, investigators were able to assemble bombs and carry them around freely.

The infiltrated⁴（浸润，渗透） buildings included the offices of a senator and a congressman⁵.

The report cited instances of guards falling asleep on the job or failing to detect explosives at x-ray scanners.

Embarrassing

Washington spends around $1bn a year protecting thousands of government buildings across the country.

The BBC's Jon Donnison in Washington says the report makes embarrassing reading for the Federal Protection Service, which employs over 13,000 contract security guards.

The report flagged up an incident where one guard accidently fired his gun into a mirror in a public lavatory⁶（盥洗室，厕所） while practicing pulling it out of its holster（手枪皮套）.

On another occasion, a security officer did not notice that he had sent a baby through an X-ray machine.

The Senate Homeland Security Committee is due to hold a hearing into failings at the agency.

The committee chairman, Senator Joe Lieberman, said that eight years after the 9/11 attacks, it was "simply unacceptable" that federal employees and visitors remained exposed to potential terrorist attacks.