Foreign nationals caught using fraudulent documents to enter the country through the San Luis port of entry are now being prosecuted for identity theft.

Since January, the U.S. Customs and Border Protection has initiated a zero-tolerance policy targeting those who use false identification to cross the border.

According to the U.S. District Attorney's Office in Phoenix, 118 individuals were caught trying to enter the U.S. with fake documents at the San Luis port of entry during the first five months of 2009.

Each was charged with a federal misdemeanor.

The CBP said in an effort to ensure legitimate trade and travel, the identity and citizenship of everyone making entry into the United States is checked  to determine their admissibility and intent.

Brian Levin, CBP public affairs officer for southern Arizona, said most of the fraudulent documents they confiscate are border crossing cards, passports or visas from other countries. He said agents will also occasionally discover fake U.S. documents.

"The majority of these cases involve people who use documents belonging to somebody else. Others will alter an original document by adding their photo, or by using a document that is completely fake."  

Levin said some of the counterfeit documents are surprisingly accurate while others are easily identifiable as fraudulent.

"Our officers are trained to look for specific security features built into the documents. They are also trained to pick up on the features of a person to see if they are an impostor by comparing them to their photo ID or to other information in our database."

The CBP said in an effort to secure the border at the ports of entry, they screen all people, vehicles and goods entering the United States, while facilitating the flow of legitimate trade and travel.

"We want people to know our officers have the opportunity to screen those who might be using fraudulent ID," said Levin.

"We are engaged in this fight and we want to put a stop to it to make sure everyone coming into this country is legitimate. We are remaining vigilant to intercept these type of crimes."