U.S. Sen. Kirsten Gillibrand does not want the recently installed interim U.S. attorney in Manhattan to become the official head of the nation's oldest federal prosecutor's office.

According to a statement from a spokesman released Wednesday, Gillibrand intends to use her “blue slip prerogative” to block Geoffrey Berman's all-but-certain nomination by President Donald Trump. As with all U.S. attorneys, Berman requires Senate approval to take his place as the head of the Manhattan prosecutor's office.

Berman was appointed as an interim by U.S. Attorney General Jeff Sessions earlier this month. The appointment allows Berman to remain in the office for 120 days in lieu of a nomination by the president, and approval by the U.S. Senate.

The statement released by Gillibrand's office takes issue more with the process leading up to Berman's appointment than with Berman himself. The statement from spokesman Glen Caplin refers to the “unusual step” Trump reportedly took of personally interviewing Berman, calling the move “deeply disturbing considering the conflicts of interest inherent by his potential jurisdiction on matters that could affect the president personally.”

Berman would, as U.S. attorney, potentially have jurisdiction over much of the president's business and personal interests, as Trump Tower resides in the Southern District of New York. Likewise, the office is already reportedly working in conjunction with special counsel Robert Mueller's investigation into Russia's meddling in the 2016 election. Reports indicate prosecutors in Manhattan were investigating former Trump campaign chairman Paul Manafort alongside Mueller's probe.

Manafort was indicted in Washington, D.C., last year on money laundering conspiracy and other charges.

Additional actions by the president raised concerns for Gillibrand, according to her spokesman. According to former FBI Director James Comey, who's firing prompted Mueller's appointment, Trump asked for his personal loyalty shortly during a meeting between the two. “In light” of this reported meeting, Berman's own direct meeting with Trump ahead of his appointment, and a presumed nomination, appeared to cross a line for Gillibrand, who believes the move should be “disqualifying for a nominee,” Caplin said.

“Senator Gillibrand believes U.S. attorneys work for the people they serve and must be independent from the executive branch. That is a cornerstone of our democracy,” Caplin said in his statement. “Under these circumstances, if nominated, the senator would have no choice but to stand up for the independence of the U.S. Attorney's Office by using her blue slip prerogative.”

A spokesman for the U.S. Attorney's Office in Manhattan did not immediately respond to a request for comment.