Washington(CNN) The FBI has lost several informants that had penetrated groups at the center of terrorism investigations.
A task force targeting interstate meth and heroin traffickers has run out of funds to pay for controlled purchases.
Agents working a multi-year MS-13 investigation have resorted to conference calls to communicate with Spanish-speaking sources.
As the partial government shutdown entered a second month, dozens of anonymous FBI officials took the rare step to share how the lack of funding has kneecapped operations in a report released Tuesday by an agents advocacy group.
The accounts -- compiled by the FBI Agents Association, which represents most of the bureau's active duty special agents -- mark a new front in the damage caused by the country's longest shutdown: weakened national security.
"The shutdown has eliminated any ability to operate," an agent working undercover counterintelligence cases said in the report. "The fear is our enemies know they can run freely."
In a statement, the FBI distanced itself from the report.
"Earlier today, the FBI Agents Association (FBIAA) released a report entitled 'Voices From the Field: FBI Agent Accounts of the Real Consequences of the Government Shutdown.' This report is a product of the FBIAA, a nonprofit professional association, and was not issued by the FBI," the statement read.
The shutdown, which has already left scores of Americans without pay and forced into lines at food banks, showed no signs of resolution on Tuesday as President Donald Trump continued to criticize congressional Democrats who have so far refused to support new funding for his administration's desired wall across the US-Mexico border.
In the meantime, FBI leadership has had to spread out a dwindling operational budget to agents across the globe, at times tying the hands of investigators who said in the report that they were unable to pay for grand jury subpoenas and informants who deliver critical information.
Multiple FBI officials working in counterterrorism described in the report how the inability to pay informants had affected their investigations.
"We have lost several sources who have worked for months, and years, to penetrate groups and target subjects," said one joint terrorism task force coordinator.
"Not being able to pay Confidential Human Sources risks losing them and the information they provide FOREVER. It is not a switch that we can turn on and off," another official said.
The FBI's targeting of MS-13, a street gang that uses particularly vicious methods and has become a leading public enemy of the President, has also been hampered, according to an official investigating the group.
"Since the shutdown, I have not had a Spanish speaker in the Division," the official said in the report. "We have several Spanish speaking informants. We are only able to communicate using a three way call with a linguist in another division."
The FBI declined to comment on the anonymous anecdotes in the report.
Nearly 5,000 members of the FBI, including intelligence analysts and support staff, have been told to stay home as the shutdown continues. All of the bureau's 35,000 employees will miss their second consecutive paycheck at the end of this week.
Employees have also been told their vision and dental insurance will lapse beginning this Friday, though their medical coverage will remain, according to Tom O'Connor, the president of the agents association.
A number of the anonymous officials in the report also sounded off on the impact the financial insecurity caused by the shutdown is having on the lives of the law enforcement agents.
"I have heard from some of the younger employees. If this shutdown is a prolonged matter, they said they would find work elsewhere," one official told the agents association.
Recruitment of future talent is also in danger. "These folks will go elsewhere too and we will get stuck with sub-par applicants," O'Connor said at a news conference Tuesday.