Congressional Republicans filed a joint letter to President Biden Thursday, demanding greater transparency and more active cooperation with investigations into the origins of the COVID-19 pandemic. GOP officials say that sources in the federal government and military who have been tapped for information regarding the pandemic have failed to properly respond.

"We are writing to express our concern with a lack of responsiveness to requests to Ranking Members from our Committees on the topic of the origins of COVID-19," the letter states. "Disappointingly, many of us have received unsatisfactory responses, or no response at all.

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"Requests for documents, briefings, or written responses for questions were refused, citing your request that the Intelligence Community review its holdings regarding the origins of COVID-19."

WASHINGTON, DC - AUGUST 25: Rep. Michael McCaul (R-TX), speaks at a bipartisan news conference on the ongoing Afghanistan evacuations, at the U.S. Capitol on August 25, 2021 in Washington, DC. McCaul urged President Biden to continue to evacuate all American's and those with special immigrant visas. (Photo by Kevin Dietsch/Getty Images)

Rep. Michael McCaul, R-Texas, speaks at a bipartisan news conference on the ongoing Afghanistan evacuations at the U.S. Capitol Aug. 25, 2021, in Washington. (Kevin Dietsch/Getty Images)

The letter, sent by GOP Reps. Michael McCaul, Texas; Frank Lucas, Okla.; and Cathy McMorris Rodgers, Wash., raises issues with a number of perceived gaps in public knowledge, including military research and intelligence.

"Additionally, there remain many outstanding questions regarding the origins of COVID-19, the nature of classified military research conducted at the Wuhan Institute of Virology, and how funding from the United States supported that research. As such, we reiterate our request that you declassify all relevant intelligence on this matter, as far as possible while protecting sources and methods. Congress and the American people have a right to know."

WASHINGTON, DC - APRIL 02: Rep. Cathy McMorris Rodgers (R-WA) questions Gov. Jay Inslee (D-WA) during a House Energy and Commerce Environment and Climate Change Subcommittee hearing on Capitol Hill on April 2, 2019 in Washington, DC. Inslee, who is a candidate for president in 2020, has said that he will make climate change the centerpiece of his campaign. (Photo by Zach Gibson/Getty Images)

Rep. Cathy McMorris Rodgers, R-Wash., questions Gov. Jay Inslee, D-Wash., during a House Energy and Commerce Environment and Climate Change Subcommittee hearing on Capitol Hill on April 2, 2019, in Washington. (Zach Gibson/Getty Images)

The Republican representatives cited in their complaint a standard touted by the Trump administration. The former president's White House asserted that it would "voluntarily release information" when possible.

"In light of these precedents, we request that your administration clarify whether it will adhere to judicial precedent and Executive Branch policy and practice on responding to Congressional requests from Ranking Members of the Committee in good faith exhibiting proper respect," the letter states. 

"In addition, we urge you to direct your administration to adequately respond to our requests in a manner consistent with Congress' oversight roles and our Constitutional principle of co-equal branches of government. "

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House Foreign Affairs Committee Republicans released the results of their probe into the possible origins of COVID-19 in August, with ranking member McCaul accusing the Chinese Communist Party (CCP) of engaging in the "greatest cover-up in human history."

President Biden

President Biden speaks about the government's COVID-19 response in the South Court Auditorium in the Eisenhower Executive Office Building on the White House campus in Washington, Jan. 13, 2022. (AP Photo/Andrew Harnik)

"They were playing with fire," McCaul said. "They were genetically manipulating at the lab this gain-of-function that was taking place."

Many of the key points from the report focused on activities in and around Wuhan that appeared to indicate the virus may have been circulating in China as early as September 2019, well before the World Health Organization's Country Office in the People’s Republic of China picked up a press statement on Dec. 31, 2019, by the Wuhan Municipal Health Commission from its website on cases of "viral pneumonia" in Wuhan.

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A government watchdog group filed a lawsuit Thursday demanding information about the actions of National Institute of Allergy and Infectious Diseases (NIAID) Director Dr. Anthony Fauci in the early days of the pandemic.

Fox News' Brian Flood contributed to this report.