Since 2012, over 650,000 illegal immigrants have been granted amnesty under the Obama administration's Deferred Action for Childhood Arrival program, including more than 4,000 suspected of being involved with fraud, gangs or terrorism, according to the U.S. Citizenship and Immigration Services.

Written responses provided by USCIS to Senate Judiciary Immigration and the National Interest Subcommittee Republicans say that as of March, 664,607 illegal immigrants were granted amnesty and 243,872 renewals were approved under DACA, while 43,375 initial requests and 414 renewals were denied, according to Breitbart.

President Obama proposed DACA in 2012, allowing younger illegal aliens who came to the U.S. before June 2007 to apply for a renewable work permit and exemption from deportation, the Washington Examiner reported.

Of those approved for amnesty, 3,959 were suspected of fraud, at least 49 had ties to gangs and six had potential links to terrorism.

The agency revealed that it does not track gang, money laundering or drug cartel affiliations among DACA applicants, saying it only discovered the ties after a recent database search for suspected gang associations.

In all, the Obama administration identified 16 DACA requests that posed "possible national security concerns," but only seven of those have been denied amnesty, while three remain pending, according to Breitbart.

"Each case was individually vetted and deconflicted with the appropriate law enforcement agency, and each request was considered on its individual merits," USCIS said in its written response.

Out of 748,789 total initial requests and 355,805 renewal requests, USCIS has only interviewed 283 DACA applicants in person, representing about .02 percent of all DACA applications.

USCIS said that applications for permanent residence have far surpassed projections, surging from 3,000 to 7,500 a month.

The agency is producing 144,275 employment authorization documents per month and is capable of approving 400,000 work permits a month.

As for the future of the program, USCIS said it expects the FY 2015 caseload will require 331 full time employees.

"USCIS forecasts that in FY15, the DACA caseload will require the full time equivalent of 331 federal employees, including adjudicators, clerical and mission support personnel, as well as supervisors and managers. All costs associated with consideration of DACA requests, including USCIS personnel responsible for processing DACA requests, will be paid for through DACA-related fees," USCIS wrote.