FBI Director James Comey will testify before the House Intelligence Committee on Monday at a closely watched hearing.

So far, Comey has not made any detailed public comments on what are expected to be two key subjects of the hearing: reported investigations into contacts between the Trump campaign and the Russians, and President Trump’s wiretapping claims.

Here’s what you need to know:

Trump’s wiretapping claims

President Trump claimed, in several early-morning tweets on March 4, that his phones had been tapped throughout the election by then-President Obama.

A spokesman for Obama called the accusation “false” and said “neither President Obama nor any White House official ever ordered surveillance on any U.S. citizen."

Attorney General Jeff Sessions has suggested he never provided information to Trump that may have supported the wiretapping allegation.

On March 5, the White House called for Congress to investigate—now, lawmakers in both chambers of Congress are demanding the FBI clear up the president’s claims.

Both the House Intelligence Committee and Senate Judiciary Subcommittee on Crime and Terrorism asked the Justice Department to turn over any evidence supporting Trump’s allegations – including warrants and court orders. The DOJ said Friday it had "complied" with requests for information.

The leaders of the House and Senate Intelligence committees said earlier last week they didn't have evidence to back up the president’s wiretapping allegations.

Claims on Trump campaign contact with Russia

The New York Times and CNN reported in February that U.S. intelligence officials had evidence of repeated contacts between some Trump campaign associates and Russian officials. The Trump campaign denied any such contact.

Attorney General Sessions held two meetings with the Russian ambassador last year, despite testimony before a Senate committee during his confirmation hearing that he had no communications with the Russians.

Sessions said that the meetings were not about the campaign, but rather in his capacity as a member of the Senate Armed Services Committee.

Reports surfaced in February that Michael Flynn, then Trump’s national security adviser, had inappropriately discussed sanctions on Russia with the country’s ambassador before the inauguration and misled Vice President Pence. Flynn later had to resign amid the controversy.

There are also claims that former Trump Campaign Manager Paul Manafort, had been in contact with Russian officials. A New York Times report said the FBI found evidence of this relationship—an allegation Manafort, who does business in Ukraine, has also denied.

These allegations all come in the midst of a “dossier” allegedly compiled by a British intelligence official on behalf of Trump opponents during the campaign, which was created with the purpose to outline evidence that Trump, himself, had deep ties to Russia. The credibility of the dossier has been widely challenged.

Tune into Fox News Channel for special coverage of the hearing at 10 a.m. EST. Bret Baier and Shannon Bream anchor out of Washington.