The special counsel overseeing the government’s investigation into possible Trump campaign ties to Russia has approved former FBI director James Comey to testify before a Senate committee pursuing the same matter, a Comey associate said Wednesday.

It wasn’t immediately clear what exactly Comey plans to tell the Senate Select Committee on Intelligence, though lawmakers are certainly likely to ask Comey about his interactions with President Trump as the bureau pursued its investigation into his campaign’s contacts. Associates have said Comey wrote internal memos describing certain interactions with Trump that gave him pause in the months after his election, including details of a dinner in which he claimed the president asked him to pledge his loyalty, and a request to shut down the investigation of a former top aide.

The associate, who wasn’t authorized to discuss details of the testimony spoke Wednesday on condition of anonymity, declined to discuss the content of Comey’s planned testimony, other than to say that Robert Mueller III, who was appointed earlier this month by the Department of Justice to lead the government’s inquiry, is allowing Comey to make certain statements.

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A spokesman for Mueller, a former FBI director, declined to comment. Mueller’s separate probe could conceivably look at the circumstances surrounding Comey’s firing.

Congress is currently out of session. It resumes next Tuesday. No date for testimony has been set.

The Associated Press reported earlier this month that Comey planned to testify before the Senate committee after Memorial Day, but the approval from Mueller to do so could indicate that date is fast approaching.

A spokeswoman for the committee’s chairman, Sen. Richard Burr, R-N.C., said the committee “welcomes the testimony of former director Comey” but declined to comment further.

The House panel pursuing its own investigation of the Trump campaign and possible Russia ties has also sought information from Comey, asking the FBI to turn over documents related to his interactions with both the White House and the Justice Department.

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Trump has repeatedly dismissed allegations that his campaign collaborated with Russia ahead of the presidential election. Early Wednesday morning, the president tweeted “Witch Hunt!” in reference to testimony by Comey and former CIA director John Brennan before Congress on the topic.

But later in the day, the White House showed it was beginning to offload the Russia crisis to Trump’s longtime personal attorney, Marc Kasowitz.

At a Wednesday briefing, press secretary Sean Spicer refused to answer a reporter’s questions about developments in the probe, saying all such inquiries must be directed to Trump’s outside counsel. It marked the first time the White House officially acknowledged that outside counsel had been retained.

Calls and emails to Kasowitz’s New York firm were not immediately returned on Wednesday.

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Associated Press writers Julie Bykowicz, and Deb Riechmann contributed to this report from Washington, D.C.