U.S. Immigration and Customs Enforcement "does not know exactly how many veterans have been placed in removal proceedings or removed, or if their cases have been handled according to ICE's policies," a federal watchdog report found Thursday.

The new report, conducted by the Government Accountability Office, examined issues around the deportation of veterans who are not citizens. It found that while ICE has policies for handling deportation cases that concern veterans, the agency applies them inconsistently and does not maintain data that tracks veterans.

The watchdog recommended that ICE make changes to implement its current policies consistently, start building an electronic database of veterans in deportation proceedings and take steps to ensure officers are properly identifying and documenting when an immigrant they encounter is a veteran.

Military service has long been an expedited pathway toward citizenship for many legal residents, but not all who serve become citizens. Some veterans do not realize they have to apply once they become eligible through their service, while others may not be eligible based on other citizenship requirements, such as a disqualifying criminal record. From 2013-18, more than 44,000 noncitizens enlisted in the military, according to Department of Defense data.

ICE policies require that when agents and officers learn they have encountered a veteran who they believe may be deportable, they must conduct additional assessments that take the person's service history into account and get management approval to proceed with the case.

The GAO found ICE placed at least 250 veterans in deportation procedures over the last five years, based on available data. But, the authors noted, the actual number could be much higher, because the agency does not properly track veterans in its systems.

"None of the three ICE components who encounter veterans ... maintain complete electronic data on the veterans they identify," the report states.

It also found that of the nearly 90 veterans who were deported from 2013 to 2018, agents failed to get the required management approval in 21 percent of their cases and failed to elevate cases to headquarters for 70 percent of those that required it.

When asked about the policies in December 2018, officials with Homeland Security Investigations, a law enforcement arm of ICE, told the GAO that they had not been adhering to the two policies, "because they were unaware of the policies prior to [the] review."

The two policies were from 2004 and 2015.

"Without developing and implementing a new policy or revising its 2004 and 2015 policies to require agents and officers to ask about and document veteran status, ICE has no way of knowing whether it has identified all of the veterans it has encountered," the watchdog wrote.

In response to questions from the watchdog, according to the report, ICE officials said the policies are intended to provide guidance and direction for handling cases of potentially deportable veterans, but could be updated with additional guidance to ask immigrants about veteran status.

The report was commissioned by four members of Congress in 2017, including Rep. Mark Takano, D-Calif., now chairman of the House Committee on Veterans' Affairs.

Takano and Rep. Juan Vargas, D-Calif., sent a letter to the acting director of ICE Thursday, asking how the agency will make changes based on the report's findings.

"We cannot allow noncitizen veterans to fall through the cracks of our broken immigration system," Takano said.