WASHINGTON — TheWhite Housesaid Thursday that it has fired a member of the Surface Transportation Board, a move that comes as the independent federal regulatory agency is considering theproposed mergerof Union Pacific and Norfolk Southern railroad companies. "Earlier this evening, I received an email from the White House purporting to terminate my position at the Surface Transportation Board," Robert Primus wrote ina post to LinkedInon Wednesday. "This is deeply troubling and legally invalid." Primus' termination, which was first reported byThe Wall Street Journal,comes as the White House has increasingly moved toexert controlover agencies across the federal government, including those considered to be independent. Primus said in his post that he planned to "continue to discharge my duties as a member of the Board and, if I'm prevented from doing so, I will explore my legal options." The Presidential Personnel Office — which is now set to be run by longtime Trump aideDan Scavino— did not offer a reason for Primus' dismissal, according to a copy of the email seen by MSNBC. Staff member Mary Sprowls said that his position as a member was terminated "effective immediately." Access to Primus' government devices was shut off on Wednesday evening, according to a person familiar with matter. Reached for comment, a White House spokesperson did not provide a specific reason for Primus' firing. "Robert Primus did not align with the President's America First agenda, and was terminated from his position by the White House," White House spokesperson Kush Desai said in a statement. "The Administration intends to nominate new, more qualified members to the Surface Transportation Board in short order." The board did not immediately respond to a request for comment. The Surface Transportation Board began the regulatory review process for the proposed railway merger in July, after Union Pacificannouncedthat it would acquire Norfolk Southern at a price tag of $85 billion. The deal, which would create the nation's first transcontinental railroad, is still under review by the board. The proposal has facedpushbackfrom labor unions and sparked controversy over its potential impact on competition in the railroad industry. Primus' term was set to end in 2027, according to the board's website. He wasconfirmedto the board in the final months of President Donald Trump's first term and became the chairman during the Biden administration. A new chairman was appointed at the start of Trump's second term. The board typically has five members, and Congress designed it to ensure that it would not be dominated solely by one political party. There is one remaining Democrat on the board and two vacancies. Before joining the Surface Transportation Board, Primusworked withseveral Democratic members of Congress. The Trump administration has increasingly moved to exert more control over agencies, working to oust officials whom the White House deems insufficient to carry out the president's agenda. Earlier this week, Trump announced he wasmoving to fireFederal Reserve governor Lisa Cook, though Cook sued Trump Thursday morning. On Wednesday, the Trump administration fired Centers for Disease Control and Prevention DirectorSusan Monarez,prompting several other top health officials to exit the agency in protest. In January, Trumpfired two Democratic commissionersat the Equal Employment Opportunity Commission. In March, he fired two Democratic commissioners at theFederal Trade Commission.In May,Trump firedthe Librarian of Congress, and then later fired the head of theU.S. Copyright Office. The Trump administration has also fired a member of theNational Labor Relations Board, the NLRB's general counsel and the head of the ethics watchdog, the Office of Special Counsel. He alsodismissed the headof the National Archives, going on to install Secretary of State Marco Rubio as the acting head. The Supreme Court previouslyhanded Trump a winin legal battles over his firings of independent agency members, temporarily blocking a lower court that ruled that two fired officials should be reinstated. The high court has also indicated that the Federal Reserve could betreated differently, calling it a "uniquely structured, quasi-private entity." The separate distinction sets up what is expected to be a high-profile legal battle as Cook challenges Trump's firing.