Originally Published: 31 MAY 23 10:37 ET

Updated: 31 MAY 23 12:03 ET

By Sara Murray and Alayna Treene, CNN

(CNN) — FBI Director Christopher Wray is scheduled to speak Wednesday with House Oversight Chairman James Comer and Iowa Sen. Chuck Grassley regarding a dispute over an internal law enforcement document that Republicans believe will shed light into an allegation that then-Vice President Joe Biden was involved in a criminal scheme with a foreign national.

The FBI said it is cooperating and has offered to allow Republicans to see the document but has so far refused to hand it over because it contains raw and unsubstantiated intelligence. Comer, however, has threatened to hold the FBI director in contempt of Congress if the bureau refuses to comply with a subpoena.

The call is scheduled for 1:30 p.m. ET, Comer spokesperson Austin Hacker said.

Rep. Jamie Raskin, the top Democrat on the House Oversight Committee, also asked to join Wednesday’s call with Wray, a request Comer denied, a Democratic committee spokesperson said. A GOP committee spokesperson said the call is “not another opportunity for Ranking Member Raskin to minimize whistleblower revelations and undermine the authorities of the very institution that he represents.”

The document is an FD-1023 form, which the FBI uses to memorialize information gathered from confidential sources. It typically includes allegations from a source that have not been verified by the FBI. According to Comer, the one in question, dated June 30, 2020, says the foreign national allegedly paid $5 million to receive a desired policy outcome, based on unclassified and legally protected whistleblower disclosures.

In a recent letter to Wray and Attorney General Merrick Garland, Comer and Grassley wrote, “It has been alleged that the document includes a precise description of how the alleged criminal scheme was employed as well as its purpose.”

The White House has previously dismissed the unverified claim as another one of Republicans’ “unfounded politically-motivated attacks.”

The FBI, in a letter sent prior to Comer’s contempt threat, said it will make the information available to the oversight committee “in a format and setting that maintains confidentiality and protects important security interests and the integrity of FBI investigations.” The FBI also said there are limitations on its ability to share unsubstantiated raw intelligence outside the bureau.

Since taking control of the House earlier this year, Republicans have aggressively pursued Biden and his family, particularly his son Hunter Biden, over allegations that they improperly used the now-president’s political connections to enrich themselves. Earlier this month, Comer alleged that the Biden family received millions of dollars in payments from foreign entities in China and Romania, including when Biden was vice president. The committee does not suggest any illegality about the payments from foreign sources and representatives for the White House and Hunter Biden have dismissed the allegations as politically motivated.