A top Justice Department official has told Sen. Lindsey Graham, R-S.C., that Deputy Attorney General Rod Rosenstein will continue in his oversight role of special counsel Robert Mueller, and will only recuse himself if “deemed appropriate by department officials.”

The South Carolina Republican had written to Rosenstein, who oversees Mueller’s probe, asking if he should recuse himself due to a conflict of interest.

In a Wednesday letter obtained by the Washington Examiner, Assistant Attorney General Stephen Boyd writes that “investigations of ongoing efforts by foreign agents to influence our government are complex and extraordinarily important.”

“Nonetheless, [Rosenstein] would recuse from all or part of any matter if recusal were deemed appropriate by Department officials who are informed about the matter,” wrote Boyd. “Otherwise, he has a responsibility to fulfill his oath to well and faithfully execute the duties of his office.”

DOJ Letter to Graham on Rosenstein recusal by Washington Examiner on Scribd

Graham is expected to respond to the letter later Wednesday in an interview with Fox News.

In his May 31 letter, Graham asked Rosenstein if he considers himself a potential witness in Mueller’s investigation.

“If not, why not?” he wrote. “If so, should you recuse yourself from further interactions with and oversight of the Mueller investigation?”

Rosenstein appointed Mueller as special counsel in May 2017 after the recusal of Attorney General Jeff Sessions.

Rosenstein is acting attorney general in this situation, and has oversight into every move the Mueller investigation makes. He is also the only DOJ official with constitutional authority to fire the special counsel.

Mueller is investigating Russian interference in the 2016 presidential election and possible links to the Trump campaign. He is also investigating if President Trump obstructed justice when he fired former FBI Director James Comey, which happened less than two weeks before Mueller was appointed.

Graham noted that Trump relied on a memo written by Rosenstein to fire Comey, and wondered if that could be the source of a potential Rosenstein-Mueller conflict.

Graham's questioning of Rosenstein now makes him one of the lone Senate Republicans who has thus far waded into a tense situation between Trump-allied House Republicans and the Justice Department.

House Republicans have accused Rosenstein and the Justice Department of stonewalling their attempts to get access to documents they've requested about various matters, from the Russia investigation to the Hillary Clinton email probe — though the Justice Department and FBI have turned over thousands of pages of documents, and briefed certain lawmakers on those documents.

The pressure from Graham, a top Senate Republican, adds yet another layer to the public criticisms of Sessions by President Trump, who has renewed attacks against his attorney general in recent days for recusing himself from the Russia investigation in the first place.