Scam artists claiming to work for "U.S. Immigration" are calling victims across the country seeking to steal their personal information and commit identity theft, the Department of Homeland Security's inspector general warned.

The thieves are using a technique called spoofing, where they alter the caller ID so it looks like the call is coming from the Department of Homeland's hotline number (1-800-323-8603).

"The scammers demand to obtain or verify personally identifiable information from their victims through various tactics, including by telling individuals that they are the victims of identity theft," the U.S. Department of Homeland Security's Office of Inspector General said in its fraud alert Wednesday. It also noted that many of the scammers "reportedly have pronounced accents."

The inspector general said DHS never uses its hotline to make outgoing calls. It only uses the number to receive information from the public. It said individuals shouldn't answer calls from 1-800-323-8603, and if they do, they shouldn't divulge personal information.

Arlen Morales, a spokesman for the agency told CNNMoney that this is the first time that the hotline has been spoofed and that it has received about a dozen complaints about the scam.

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While that number may appear small, Erin Quinn, a staff attorney at the Immigrant Legal Resource Center, said the number of occurrences is likely much higher. She noted that immigrants often are afraid to come forward to report scams for fear of being ensnared in the heightened immigration enforcement dragnet.

Quinn said that she has heard of several instances in which the phone numbers for local offices of U.S. Customs and Immigration Services have been fraudulently copied and used to scam victims.

Joanne Talbot, a USCIS spokeswoman, recalled a spoofing scam in 2013 in which immigrants applying for visas, green cards and citizenship were targeted. "The scammer poses as a USCIS official and requests personal information (such as Social Security number, passport number, or A-number), identifies supposed issues in the recipient's immigration records, and asks for payment to correct these records," Ferreira wrote in an email.

Talbot also noted that USCIS never asks for any personal information or form of payment over the phone.

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Fraudsters have also used phone spoofing to impersonate Internal Revenue Service agents, threatening vulnerable people like immigrants with deportation or the loss of their diver's license if they don't pay what they owe immediately.

In October, the Department of Justice filed charges against 56 individuals and five call centers, alleging they were part of a transnational criminal organization that stole millions of dollars from tens of thousands of victims through telephone impersonation scams.

Earlier this month, Bharat Patel, an Indian national living in Illinois pleaded guilty for his role in liquidating and laundering victim payments generated through the scams, according to a USCIS press release.

According to admissions from his plea, Patel, 43, worked with people in call centers in Ahmedabad, India, who impersonated officials from the IRS or U.S. Citizenship and Immigration Services and defrauded U.S. victims. Patel said the call center operators used information from data brokers and other sources to target victims who were then threatened with arrest, imprisonment, fines or deportation if they did not pay money they allegedly owed the government.

Patel is scheduled to be sentenced on July 7. Other cases are still pending.

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Immigrant advocates say that they have seen an uptick in frauds targeting immigrants in recent months.

"Generally we see an uptick in scams when there is fear in the community," Quinn said. "Any change in policy, even if it's a positive policy change, can increase the number of scams against immigrants and others."

This makes it even more important for immigrants to be vigilant if they receive a suspicious call, they say.

"As scammers seek to capitalize on the anti-immigrant political climate, people should know never to offer payment or personal information over the phone," said Steve Choi, executive director of the New York Immigration Coalition. "All official, government requests will come by mail from a verifiable address with a case reference number," he said.