Nearly 40 illegal immigrants hired by contractors working on three military bases in Georgia, Virginia and Nevada were arrested over the last three days by U.S. Immigration and Customs Enforcement agents, the agency said Friday.

In the largest arrest, 21 illegal immigrant workers were charged with identity theft and immigration violations for attempting to enter Fort Benning, Georgia, said agency spokesman Richard Rocha. They were among 24 workers arrested Wednesday while trying to enter the base to do construction work on soldiers' barracks. The three workers who are not facing criminal charges will be placed in immigration removal proceedings.

Similar raids at military installations in Nevada and Virginia on Thursday also netted 18 other arrests, Immigration and Customs Enforcement spokesman Marc Raimondi said.

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One of those arrested, a Nicaraguan man employed by a company doing construction at Creech Air Force Base in Indian Springs, Nevada, was a member of MS-13, which the government considers one of the most dangerous gangs in the U.S., Raimondi said. None of the others arrested posed a direct security threat, Raimondi said, though he added that it is critical that authorities have real identifications for those entering military bases.

The group arrested in Georgia includes 20 Mexican nationals, three Guatemalans and an Italian. Nine of the 21 are charged with either possessing or using fraudulent identity documents, and another was accused of re-entering the country after deportation. The remaining 11 defendants are accused of entering the country illegally.

Immigration and Customs Enforcement spokesman Richard Rocha on Friday declined to provide details, including the names of the arrested workers. Rocha said the workers worked for different subcontractors, who are not currently facing any charges from federal officials.

Many of the workers used counterfeit identity documents to obtain jobs and three had entered the United States legally but their eligibility to stay in the country had expired, the news release said. It also said the arrests resulted from a seven-month, multi-agency investigation.

The 16 people arrested in Virginia include 14 undocumented workers who are not facing criminal charges, including three arrested at the Quantico Marine Base. Two men, an American a Mexican, were arrested at an apartment complex in nearby Dumfries, Virginia, and charged with conspiracy to harbor illegal aliens, whom they are accused of then hiring for work on the Marine base.

Military installations and other structures considered critical to national security have been a high priority for immigration officials as they have stepped up efforts to crack down on illegal workers over ther last year, said Assistant Secretary for Immigration and Customs Enforcement Julie Myers.

In July, the agency arrested nearly 60 illegal immigrants at Fort Bragg in North Carolina.

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