The directors of the Federal Bureau of Investigation and National Security Agency will break their public silence on Monday about their investigations into possible links between Russia and President Donald Trump's campaign at a rare open congressional intelligence committee hearing. Representatives Devin Nunes, chairman of the House of Representatives Permanent Select Committee on Intelligence, and Adam Schiff, the panel's top Democrat, have called FBI Director James Comey and NSA Director Admiral Mike Rogers to testify as part of their committee's probe into allegations that Russia meddled in U.S. elections. Other congressional committees also are investigating the matter, mostly behind closed doors. But amid a furor over whether Moscow tried to influence the 2016 presidential race on Trump's behalf, lawmakers said they would make public as much of their probes as possible. Russia denies attempting to influence the election, and on Monday Trump took to Twitter to once again call the allegations "fake news." Donald Trump tweet Donald Trump tweet 2 Donald Trump tweet 3 Comey and Rogers are not expected to reveal much in public about the probes, which include information that is classified Top Secret and also separated into different compartments, each of which requires a separate clearance. But the hearing could become heated as Republicans balance support for their party's leaders and Democrats vent frustration over Republican congressional leaders' refusal to appoint a special prosecutor or select committee to investigate.

FBI Director James Comey. Susan Walsh | Pool | Getty Images

Trump fired his first national security adviser, Michael Flynn, last month after he failed to disclose contacts with Russia's ambassador before Trump took office on Jan. 20. Last week, new information surfaced about more than $65,000 that Flynn was paid in 2015 by companies with links to Russia. Attorney General Jeff Sessions, a former senator, recused himself from investigating the matter after it was revealed that he did not answer accurately when he was asked during his confirmation hearing about his contacts with Russian officials during the election. He failed to disclose that, as senator, he had met with Russia's ambassador to the United States, Sergey Kislyak.

Growing frustration

Both Trump's fellow Republicans as well as Democrats in Congress said they were frustrated by what they consider the intelligence community's failure to provide enough information about any contacts with Russia, as well as Trump's claim, made without evidence, that his predecessor, Democrat Barack Obama, ordered a wiretap of Trump Tower. Schiff said he expected Comey to make clear at Monday's hearing that the allegation was unfounded. "I hope that we can put an end to this wild goose chase because what the president said was just patently false," Schiff said on NBC's "Meet the Press" on Sunday. Nunes said on "Fox News Sunday" that he was not aware of any warrant that would have allowed such a wiretap. Members of both parties have threatened to subpoena administration officials or delay confirmation hearings for Trump's nominees until their requests for information are answered. Many Democrats also are deeply unhappy with Comey for his handling of an inquiry into Democratic presidential candidate Hillary Clinton's use of a private email server, especially issuing statements about it shortly before Election Day.

Rep. Adam Schiff, D-Calif., right, ranking member of the House Permanent Select Committee on Intelligence, and Chairman Devin Nunes, R-Calif., conduct a news conference in the Capitol Visitor Center after a briefing with FBI Director James Comey about Russia, March 2, 2017. Tom Williams | CQ Roll Call | Getty Images