The ranking Democrat on the House Intelligence Committee is pressuring committee chairman Rep. Devin Nunes Devin Gerald NunesSunday shows preview: Justice Ginsburg dies, sparking partisan battle over vacancy before election Sunday shows preview: With less than two months to go, race for the White House heats up Sunday shows preview: Republicans gear up for national convention, USPS debate continues in Washington MORE (R-Calif.) to issue subpoenas for key figures in the Trump campaign and administration as part of the committee's probe into Russia's election interference.

In a letter to Nunes on Wednesday, Rep. Adam Schiff Adam Bennett SchiffTop Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence Overnight Defense: Top admiral says 'no condition' where US should conduct nuclear test 'at this time' | Intelligence chief says Congress will get some in-person election security briefings Overnight Defense: House to vote on military justice bill spurred by Vanessa Guillén death | Biden courts veterans after Trump's military controversies MORE (D-Calif.) demanded the committee subpoena several members of the Trump administration, as well as former Trump campaign officials, including Attorney General Jeff Sessions Jefferson (Jeff) Beauregard SessionsGOP set to release controversial Biden report Trump's policies on refugees are as simple as ABCs Ocasio-Cortez, Velázquez call for convention to decide Puerto Rico status MORE, White House communications director Hope Hicks Hope Charlotte HicksSenate intel leaders said Trump associates may have presented misleading testimony during Russia probe: report Cuomo turned down Trump invitation to participate in April press briefing: report Trump shakes up White House communications team MORE and former campaign manager Corey Lewandowski Corey R. LewandowskiHow Trump can win reelection: Focus on Democrats, not himself Trump Jr. distances from Bannon group, says he attended 'single' event Bannon, three others charged with defrauding donors of 'We Build The Wall' campaign MORE.

ADVERTISEMENT

Schiff also pressed Nunes to issue subpoenas to two companies, Deutsche Bank and Twitter, to obtain information related to Russian meddling efforts in the 2016 election, as well as general subpoenas to the White House for evidence of conversations between President Trump Donald John TrumpBiden leads Trump by 36 points nationally among Latinos: poll Trump dismisses climate change role in fires, says Newsom needs to manage forest better Jimmy Kimmel hits Trump for rallies while hosting Emmy Awards MORE and fired FBI Director James Comey James Brien ComeyDemocrats fear Russia interference could spoil bid to retake Senate Book: FBI sex crimes investigator helped trigger October 2016 public probe of Clinton emails Trump jabs at FBI director over testimony on Russia, antifa MORE.

Other subpoena targets he suggests include Donald Trump Jr. Don John Trump'Tiger King' star Joe Exotic requests pardon from Trump: 'Be my hero please' Zaid Jilani discusses Trump's move to cancel racial sensitivity training at federal agencies Trump International Hotel in Vancouver closes permanently MORE and Trump Organization attorney Michael Cohen.

"To date, there are dozens of important witnesses who have yet been invited, let alone compelled to come before the committee. And all too many of the witnesses who have appeared, have refused to answer direct questions of core investigative interest to the Committee, and have asserted unprecedented and risible claims of privilege," Schiff wrote.

“The integrity and independence of the Committee and Congress’ investigative and enforcement powers are at stake. To be credible, the Russia investigation cannot simply take witnesses at their word, or accept baseless assertions of privilege where none apply. Instead, the Committee must verify assertions made by witnesses in testimony, compel testimony as well as the full production of responsive documents, and, where necessary, move to enforce subpoenas," he added.

In addition, Schiff called for former White House chief strategist Stephen Bannon to be held in contempt of Congress following his refusal to answer questions related to his time on the Trump transition team. The committee should "compel the White House to permit Bannon to testify to Congress fully and without constraints," Schiff said.

Schiff has in the past threatened to hold Sessions in contempt of Congress over not producing documents as well, but did not go that far in his letter Wednesday.

The letter notes that the list of demanded subpoenas is "partial," and that Nunes and committee Republicans are refusing to issue others as well.

Hicks became the most recent target of the committee's probe on Tuesday, testifying before lawmakers for several hours. Like Bannon, she declined to answer some questions about the Trump transition and her work in the White House.

Schiff claimed Hicks had refused to answer questions on "key events such as the fabrication of that statement about the Trump Tower meeting," referring to an initial statement issued by Trump on his eldest son's meeting with a Russian lawyer who had promised "dirt" on Hillary Clinton Hillary Diane Rodham ClintonBiden leads Trump by 36 points nationally among Latinos: poll Democratic super PAC to hit Trump in battleground states over coronavirus deaths Battle lines drawn on precedent in Supreme Court fight MORE.