The Senate Judiciary Committee has reached an agreement to subpoena documents from former Trump campaign chairman Paul Manafort as part of its ongoing probe of Russian meddling in the 2016 elections, according to the top Democrat on the panel.

Sen. Dianne Feinstein (D-Calif.) told reporters Tuesday the committee had decided to subpoena documents, but a spokesman for Feinstein would not detail what documents the committee is seeking. The senator added the panel “will certainly use the subpoena power,” if necessary, to get Manafort to testify as well.

Committee Chairman Charles E. Grassley (R-Iowa) also refused to disclose details, noting while “in principle a lot of things have been agreed to,” certain matters “still have to be worked out, and we’ll wait until details are worked out till we make a final announcement.”

Manafort has long been a focus of congressional investigators looking into possible Russian interference in the 2016 presidential election.

The Senate Judiciary Committee has reached an agreement to subpoena documents from President Trump’s former campaign chairman Paul Manafort as part of its probe of Russian meddling. (Matt Rourke/Associated Press)

Manafort was personally and professionally connected to several allies of Russian President Vladi­mir Putin. At one point, he even offered a Putin ally "private briefings" on the status of the 2016 campaign, people familiar with the discussions told The Washington Post.

For the Judiciary Committee, Manafort is also a subject of interest because of his unregistered lobbying activities on behalf of a Ukrainian political party with pro-Russian ties.

During the summer, Manafort spoke with Senate Intelligence Committee investigators as part of their probe into alleged collusion between Trump surrogates and Kremlin officials. The Judiciary Committee has never gotten an opportunity to interview Manafort.

Grassley and Feinstein subpoenaed Manafort once during the summer for documents and testimony — but they then dropped the subpoena to negotiate terms for an interview. The very next day, Manafort’s Arlington, Va., home was raided by the FBI.

In recent weeks, several panel members have noted, Manafort has not been responsive to the committee’s requests.

Former Trump campaign adviser Roger Stone, who was at the Capitol on Tuesday speaking with House Intelligence Committee members, later told reporters the predawn raid had shocked Manafort as “outrageous.”

Stone also said Manafort had informed him, through their attorneys, that special counsel Robert S. Mueller III planned to indict him, as first reported in the New York Times.

Neither Stone nor Manafort knows on what charge Manafort might be indicted, Stone said.

“The special counsel will try to manufacture a crime and then say ‘look Manafort, we won’t prosecute this if you say you were colluding with the Russians,’” Stone said. Manafort “is not going to lie and that would be a lie.”

Stone added he hoped the president would fire Mueller.

There is little appetite for that in the Senate, where senators on the Judiciary panel spent Tuesday morning debating bipartisan-drafted bills restricting the president's ability to fire a special counsel. The proposals would make the president's decision to terminate a special counsel's employment subject to the review of a three-judge panel.

“Each bill is motivated by similar concerns about the current special counsel Robert S. Mueller III and his investigation into the Russian government’s efforts to interfere in the election,” Grassley said at the start of a hearing into the matter. “The president has said that he doesn’t intend to fire Mueller, and I think that he made the right decision.”

Grassley and Feinstein also announced Tuesday they had written to CIA Director Mike Pompeo, demanding “access to materials” that had been made available to the intelligence committee, and they argued were relevant to the Judiciary Committee’s Russia probe as well. Feinstein also serves as a senior member of the intelligence committee.