(CNN) The Senate judiciary committee is now going through documents that could give a fuller picture of the controversial Trump Tower meeting where Donald Trump Jr. was promised Russian dirt on Hillary Clinton's campaign -- and whether there were any improper contacts between Russian officials and Trump associates during the course of the election.

The panel's two leaders, Sens. Chuck Grassley and Dianne Feinstein, also have reviewed the contents of memos written by fired FBI Director James Comey and his interactions with President Donald Trump as the committee reviews whether there was any improper interference with the FBI investigation to Trump associates.

According to committee officials, the panel has now received roughly 20,000 pages from the Trump campaign responding to a detailed series of questions posed by the panel last month.

The committee asked for all records related to the June 2016 Trump Tower meeting when Trump Jr., the President's son-in-law Jared Kushner and former campaign chairman Paul Manafort met with Russian operatives after the younger Trump was informed the Russian government was trying to help his father's campaign.

The senators also asked the Trump campaign for a wide range of records pertaining to Russian meddling in the elections, such as any campaign contacts with or about a number of senior Russian officials, such as the former Russian Ambassador to the United States Sergey Kislyak . And the senators asked for "all communications" from senior Trump campaign advisers, such as Kushner, Manafort, the President's ex-national security adviser Michael Flynn , his attorney Michael Cohen, foreign policy adviser Carter Page and former campaign manager Corey Lewandowski.

Trump Jr. has provided another 250 pages of documents to the committee, with Manafort turning over an additional 400 pages, according to committee officials.

Moreover, the committee has received documents from the Trump administration about the Russian-American lobbyist, Rinat Akhmetshin , who also attended the Trump Tower meeting, the sources said. The committee had asked the Department of Homeland Security and State Department for information about Akhmetshin's visas, immigration paperwork, and the circumstances around his entrance into the country.

JUST WATCHED Graham: Hard to believe Russian contact 'one & done' Replay More Videos ... MUST WATCH Graham: Hard to believe Russian contact 'one & done' 03:39

The numbers of pages returned to the committee were provided by committee spokesman George Hartmann. Congressional officials declined to detail the specific contents of the records.

Committee officials also told CNN that Grassley, the chairman of the committee, and Feinstein, the top Democrat on the panel, were able to review the memos that Comey wrote after his interactions with Trump, including his allegations that Trump urged him to back away from investigating Flynn and sought loyalty from the fired FBI director. The office of the special counsel, Robert Mueller , allowed the panel's leaders to review the memos in a classified setting. but they were not allowed to take notes or hold onto copies of the documents. A similar courtesy was given to the two leaders of the Senate intelligence committee, Sens. Richard Burr and Mark Warner, according to congressional sources.

The Senate judiciary committee still has not received a response to its letter to the Justice Department about warrants the FBI sought under the Foreign Intelligence Surveillance Act as part of the bureau's probe into potential Trump and Russia collusion, congressional sources said.

In June, the panel also asked a list of questions to the White House and FBI about Kushner's security clearance form, but the panel so far has only received a response from Kushner's outside attorney, according to a committee source. It's unclear whether the panel's detailed questions -- including whether the President or anyone inside the administration intervened to ensure Kushner was eligible for a security clearance -- was answered by Kushner's attorney. A Kushner attorney declined to comment.