Jan. 6 committee subpoenas Rudy Giuliani, obtains phone records for Eric Trump, Kimberly Guilfoyle

The committee has also subpoenaed several other Trump allies.

The House select committee investigating the Jan. 6 Capitol attack targeted a range of Trump associates on Tuesday, subpoenaing former Trump lawyers Rudy Giuliani, Jenna Ellis and Sidney Powell, who pushed unfounded claims of widespread 2020 election fraud, while ABC News has also confirmed that the committee has acquired phone records from former President Donald Trump's son Eric and Kimberly Guilfoyle, the fiancee of Donald Trump Jr.

"The Select Committee’s investigation has revealed credible evidence that you publicly promoted claims that the 2020 election was stolen and participated in attempts to disrupt or delay the certification of the election results based on your allegations," the panel wrote in letters to Giuliani, Ellis, Powell and Trump aide and attorney Boris Epshteyn.

The committee also subpoenaed and obtained phone records belonging to Trump's youngest son, Eric, and Guilfoyle, who is engaged to Donald Trump Jr., according to sources. Guilfoyle also served as an adviser to the former president and spoke during the rally prior to the storming of the Capitol. Sources familiar with the matter told ABC News the subpoenas went to their phone providers and those records are now in the committee's possession. Both individuals were informed by their respective cellphone providers, the sources told ABC News.

The news was first reported by CNN.

The phone record subpoenas mark the first direct action the committee has taken against a member of the Trump family.

The group subpoenaed Tuesday worked with Trump to contest the results of the election in the fall of 2020, traveling to key states and huddling with Trump and other White House aides in the Oval Office as the president weighed how to overturn the results.

"The four individuals we’ve subpoenaed today advanced unsupported theories about election fraud, pushed efforts to overturn the election results, or were in direct contact with the former President about attempts to stop the counting of electoral votes," Chairman Bennie Thompson, D-Miss., said in a statement. "We expect these individuals to join the nearly 400 witnesses who have spoken with the Select Committee as the committee works to get answers for the American people about the violent attack on our democracy.”

Ellis also circulated two legal memos urging former Vice President Mike Pence to reject or delay the count of electoral votes on Jan. 6, the committee said.

Giuliani urged Trump to seize voting machines after being told the Department of Homeland Security lacked the authority to do so, the committee said, pointing to a report from the news website Axios and documents obtained by investigators.

The former mayor of New York City, a close Trump confidant, spoke at the Jan. 6 rally outside the White House, urging for "trial by combat" over the election results before Trump supporters marched to the Capitol.

Powell, according to the committee, reportedly urged Trump to seize voting machines to find evidence that foreign hackers had altered the election results.

Powell, Giuliani, Ellis and Epshteyn did not immediately respond to requests for comment.

Dominion Voting Systems, a Colorado-based voting machine company, has filed defamation lawsuits against both Giuliani and Powell and is seeking billions of dollars in damages over their unfounded claims of election fraud. A federal judge denied both Powell and Giuliani's efforts to have the suits dismissed.

Giuliani's law license was also suspended in New York state last year over his claims of election fraud.

ABC News' John Santucci, Olivia Rubin and Will Steakin contributed to this report.