Senate Republicans are investigating allegations that federal managers retaliated against Border Patrol agents and other Homeland Security Department officials who refused to follow President Obama's immigration policies. 

The claims indicate a dispute inside federal immigration agencies over what exactly U.S. immigration law dictates, given the cascade of executive actions and guidance from the administration over the past several years. Allegedly, agents who don't want to follow the recent orders are being punished. 

“We are aware of multiple allegations of targeting and retaliation against DHS personnel who refuse to comply with this administration’s willful disregard of our immigration laws,” members of a Senate judiciary subcommittee on immigration told Homeland Security Secretary Jeh Johnson in a letter on Tuesday.

The letter, signed by Senate Judiciary Committee Chairman Charles Grassley, R-Iowa, and others, noted the retaliation accusations have been included in lawsuits filed in federal court and aired in Capitol Hill testimony earlier this month.

Chris Cabrera, a National Border Patrol Council (Local 3307) executive, recently told the Senate Homeland Security and Governmental Affairs Committee that Border Patrol agents who repeatedly report a gathering of more than 20 illegal immigrants face retribution from managers. He said they're being taken out of the field and reassigned to processing detainees, and also assigned to low-volume areas as punishment. 

“Needless to say, agents got the message and now stay below this 20 person threshold no matter the actual size of the group,” Cabrera testified. 

Even before Obama's recent executive actions, his administration has made a series of changes to immigration enforcement. In June 2012, the Deferred Action for Childhood Arrival gave a deportation reprieve -- and the option of seeking two-year work permits -- to some illegal immigrants who entered the United States before age 16 and before 2007. The administration also prioritized its enforcement resources to focus on deporting illegal immigrants who have committed felonies and others considered dangerous, while in some cases ignoring those with lower-level offenses. 

Obama expanded those programs in November 2014 through a series of executive actions. One allows parents of citizens and legal permanent residents to seek a deportation reprieve, and three-year work permits. Another expands the population eligible under DACA, and lengthens that work permit period from two to three years. 

Many Republicans and other critics of the administration’s immigration policy have challenged the constitutionality of the measures.

And in February, a federal judge in Texas placed a temporary hold on the 2014 actions, in a case in which 26 states are challenging their constitutionality.

The Department of Homeland Security did not respond Wednesday to a request for comment.

But agents facing the consequences for not enforcing changes should come as no surprise.

Obama said in late February during a MSNBC/Telemundo town hall that Immigration and Customs Enforcement or Border Patrol officials ignoring the “new directives” will have to answer to Johnson.

“He’s been very clear about what our priorities should be,” the president said. “If somebody is working for ICE and there is a policy and they don’t follow the policy, there are going to be consequences to it.”

The subcommittee’s letter argues the president’s statements “ignore the plain language of several immigration statutes that command DHS personnel to take certain actions relating to illegal aliens, (and) the comments seem to comport with a pattern and practice of threats toward DHS personnel who seek to fulfill their duties under the law.”

The letter also asks Johnson, in part, to provide by April 13 the number of employees the department has disciplined over the last six years, and provide statistics regarding the number of lawsuits or complaints filed by department personnel. 

The letter also was signed by Sens. Jeff Sessions; David Vitter, R-La.; David Perdue, R-Ga.; John Cornyn, R-Texas; Mike Lee, R-Utah; Ted Cruz, R-Texas; and Thom Tillis, R-N.C.