Carter Page. Sergei Karpukhin/Reuters The Senate Intelligence Committee appears to have sent Carter Page and other Trump associates a letter on April 28 asking them to provide extensive information about any contact they had with Russian officials or representatives of Russian business interests since June 2015.

Page, an early foreign-policy adviser to President Donald Trump's campaign, volunteered to be interviewed by the committee in March as part of its investigation into Russia's interference in the 2016 election and whether Trump's associates colluded with Kremlin officials.

The committee, led by Republican Sen. Richard Burr and Democratic Sen. Mark Warner, asks Page to make himself available for a "closed interview with designated committee staff to be scheduled for a mutually agreeable time," according to the letter, a copy of which Page sent to Business Insider.

Paul Manafort, Michael Flynn, and Roger Stone received similar letters, according to the New York Times. Manafort served as Trump's campaign chairman and Flynn was Trump's former national security adviser. Stone is an informal adviser to Trump.

Ahead of the closed interview, the letter asks Page to provide "a list of all meetings between you and any Russian official or representative of Russian business interests which took place between June 16, 2015, and January 20, 2017," including "the date, location, all individuals present, and complete copies of any notes taken by you or on your behalf."

It also asks for information about any financial holdings Page had in Russia between June 2015-January 2017. Trump announced his presidential campaign on June 15, 2015, and was inaugurated on January 20, 2017.

It is unclear whether Flynn, Manafort, and Stone were asked to provide the same information.

Page was also asked to submit "all communications records such as email or text messages, written correspondence, and phone records, of communications which took place between June 16, 2015, and January 20, 2017, to which you and any Russian official or representative of Russian business interests was a party."

Additionally, the committee asked Page to provide a fuller look into whether anyone else in the Trump campaign may have spoken to or about Russians or Russia.

It requests "all communication records ... related in any way to Russia, conducted between you and members and advisors of the Trump campaign," as well as "a list of all meetings of which you are aware between any individual affiliated with the Trump campaign and any Russian official or representative of Russian business" between June 16, 2015, and January 20, 2017.

The letter is dated about four days after reports surfaced that more than three months into the committee's investigation, it hadn't issued any subpoenas or requested any key documents such as emails, memos, and phone records from members or associates of the Trump campaign, according to multiple media outlets.

According to Yahoo, Burr had "failed to respond to requests from the panel's Democrats to sign letters" asking for such documents. Burr's signature appears on the letter to Page.

Senate Intelligence Committee Vice Chairman Mark Warner, left, and Chairman Richard Burr. AP Photo/Susan Walsh

Page sent a lengthy response, a copy of which he provided to Business Insider.

"Although you set a range of suggested deadlines for the various extensive administrative tasks on your list over the coming weeks, I instead decided to initially get back to you today on the National Day of Prayer," Page wrote to the committee in a letter dated May 4.

"Having survived the hate crimes committed against me by the Clinton/Obama regime which were in some part pursued due to my Roman Catholic faith ... finding strength through prayer in my church and by myself has remained a core source of support throughout this ongoing comically fake inquiry," he said.

Page addressed the committee's requests, which he referred to as "cumbersome chores."

He said that while he remained "committed to helping the Senate Select Committee on Intelligence in any way that I can ... please note that any records I may have saved as a private citizen with limited technology capabilities will be minuscule in comparison to the full database of information which has already been collected under the direction of the Obama administration during last year's completely unjustified FISA warrant that targeted me for exercising my First Amendment rights."

On Friday afternoon, Burr and Warner released a joint statement saying that "the committee will consider its next steps" if Page does not provide the requested materials by listed deadlines.

"Mr. Page has indicated in correspondence to the Committee that he looks forward to working with us on the matter, and that our cooperation will help resolve what he claims are false allegations," the senators wrote. "For that to happen, Mr. Page must supply the requested documents to the Commmitee."

The FBI obtained a warrant under the Foreign Intelligence Surveillance Act last summer to monitor Page's communications, The Washington Post reported in April. The FBI reportedly is investigating Page's trips to Moscow and contact with at least one Russian official last year.

"As a lone individual, I can assure you that my personal administrative capabilities pale in comparison to the clerical juggernaut represented by the numerous staff in the executive, legislative, and judicial branches of the US government which have heretofore been allegedly involved in this unscrupulous surveillance for many months on end," Page wrote.

Page previously told Business Insider he thought the FISA requests were "unjustified." But the government's application for the warrant targeting Page has been renewed more than once, The Post reported, and "included a lengthy declaration that laid out investigators' basis for believing that Page was an agent of the Russian government and knowingly engaged in clandestine intelligence activities on behalf of Moscow."