The US House of Representatives Judiciary Committee on Tuesday invited President Donald Trump to its first impeachment hearing, scheduled for December 4, starting a new phase of the inquiry that could lead to formal charges against the president within weeks.

Trump is not required to attend the hearing. But the move allows the president and his legal team access to congressional impeachment procedures that he and other Republicans have denounced as unfair, partly because the White House has not been able to call or cross-examine witnesses.

The House Intelligence Committee, which has led the impeachment investigation into Trump’s dealings with Ukraine through weeks of closed-door testimony and televised hearings, is expected to release a formal evidence report shortly after lawmakers return to Congress on December 3 from their Thanksgiving recess.

The Judiciary panel will use the report to consider formal charges that it could recommend for a full House vote by mid-December. It gave Trump until 6PM on Sunday to advise the committee on whether he would attend the hearing, and to indicate by then who would be his counsel.

The White House did not immediately respond to a request for comment.

Representative Jerrold Nadler, the Judiciary Committee’s Democratic chairperson, told Trump in a letter that he was reminding the president that the committee’s rules allow him to attend the hearing and for his legal team to question witnesses.

The hearing, scheduled to begin at 10PM, will have legal experts, who have not yet been identified, as witnesses.

“The president has a choice to make: he can take this opportunity to be represented in the impeachment hearings, or he can stop complaining about the process,” Nadler said in a statement. “I hope that he chooses to participate.”

The impeachment probe is looking into whether Trump abused his power to pressure Ukraine to launch investigations of political rival Joe Biden and a discredited conspiracy theory promoted by Trump that Ukraine, not Russia, interfered in the 2016 US presidential election.

In an interview on Tuesday with former Fox News host Bill O’Reilly, Trump denied he directed his personal lawyer, Rudy Giuliani, who had been pushing Ukraine for the investigations, to act on his behalf in trying to get Ukraine to help turn up dirt on his political rivals.