Washington (CNN) The Trump administration was warned that ending US protections for more than 300,000 Central Americans would strengthen and grow MS-13 and gangs that President Donald Trump has called "animals ," according to an internal report obtained by CNN.

But the administration went on to end the protections for citizens of El Salvador, Haiti, Honduras and Nicaragua regardless.

The warnings came from experts at the State Department in October 2017, and were attached to a letter from then-Secretary of State Rex Tillerson to then-acting Homeland Security Secretary Elaine Duke.

The State Department also warned that ending the "temporary protected status" program could also hurt US national security and economic interests, including by driving up illegal immigration.

The program covers migrants in the US of countries that have been hit by dire conditions, such as an epidemics, civil war or natural disasters. Previous administrations spanning party had all opted to extend the protections for Central America every roughly two years.

"Many of the deportees would be accompanied by their US-born children, many of whom would be vulnerable to recruitment by gangs," warned the section on Honduras.

"The lack of legitimate employment opportunities is likely to push some repatriated TPS holders, or their children, into the gangs or other illicit employment," warned the section on El Salvador.

"With no employment and few ties, options for those returning to El Salvador and those overwhelmed by the additional competition will likely drive increased illegal migration to the United States and the growth of MS-13 and similar gangs," the report added.

Trump has called MS-13 "animals." "We have people coming into the country, or trying to come in. ... You wouldn't believe how bad these people are. These aren't people. These are animals," he said in May, later explaining he was speaking about the vicious gang.

The administration says the conditions in each country have improved from the original disaster to the point that the protected status had to end. That has created a precarious legal status for hundreds of thousands of people, many who have been in the US for upwards of two decades and have put down roots.

The documents add to growing evidence that the Department of Homeland Security set aside warnings and concerns about conditions in the countries to end the program.

For Honduras and El Salvador, the analysis notes it "would not be contrary to the U.S. national interest" to let the immigrants stay, saying they were a "stable" population that has "successfully settled" in the US.

DHS spokeswoman Katie Waldman noted that the agency made the decision based on legal requirements.

"The decision to terminate temporary protected status was made after a review of country conditions and consultation with the appropriate US government agencies," Waldman said. "Former Acting Secretary of the Department of Homeland Security Elaine Duke determined that conditions that supported the designation for TPS no longer existed, and thus, under the law, she was required to terminate TPS. The Department of Homeland Security does not make the law, we enforce it. Should members have concerns with the law, they should seek to amend it."

Administration still recommended ending program

But even as Tillerson himself warned of grave consequences in his letter, with the in-depth analysis by his experts attached, his State Department still recommended the protections be ended.

In ending the program for those four countries, the administration said the law meant its hands were tied.

That was also the finding in the documents. But the career analysts also were clear that regardless of the statute, ending the protections for citizens of those countries would not align with US interests.

"The law really restricts my ability to extend TPS," Homeland Security Secretary Kirstjen Nielsen said during a congressional hearing in April. "Some countries remain perhaps unstable and have difficult conditions, but if they are not the result of the originating designation, they must be terminated."

The October 2017 letter and supporting documents are now public as part of a Freedom of Information Act request, and were shared with CNN by the office of Sen. Bob Menendez, D-New Jersey, the ranking member on the Senate Foreign Relations Committee.

In a statement, Menendez said the administration is "knowingly putting our national security and the safety of TPS beneficiaries and U.S.-citizen children at risk," and called for it to reverse its decision.

"This document release further confirms how the Trump Administration's reckless anti-immigrant agenda jeopardizes our national security interests in Central America and the safety of TPS beneficiaries and their US citizen children," Menendez said.

In each country's case except Nicaragua, the department analysis recommended a wind-down period of 36 months before protections expired, saying immediate termination would cause the gravest risks. Tillerson recommended 18 months instead, which DHS adopted.

Tillerson in his letter also warned that Central American countries "may take retaliatory actions counter to our long-standing national security and economic interests like withdrawing their counter-narcotics and anti-gang cooperation with the United States, reducing their willingness to accept the return of their deported citizens, or refraining from efforts to control illegal migration."

El Salvador and Honduras "have some of the world's highest homicide rates, and weak law enforcement capabilities" and that the countries have limited economic options for returning nationals," Tillerson added. Those factors "will make it difficult for their respective governments to ensure the protection of returning citizens -- no less the US citizen children who may accompany their parents."

Tillerson was fired as secretary of state in March and has since been replaced by Mike Pompeo.

The documents add to a developing record that the administration seemed committed to ending TPS regardless of the consequences.

In an email from Duke to White House chief of staff John Kelly days after Tillerson's letter, Duke told Kelly she needed another six months to make up her mind on Honduras but assured him her decision would "send a clear signal that TPS in general is coming to a close." Nielsen ended the protections when that time expired.

In the same court filing that revealed that email, a Homeland Security internal intelligence assessment was also made public that found similar concerns to those of the State Department, including that ending the program could actually drive illegal immigration higher, rather than lower.