The United States House of Representatives Judiciary Committee on Tuesday invited President Donald Trump to its first impeachment hearing on December 4. This is a new phase of the investigations that may lead to formal charges against Trump within weeks, BBC reported.

Jerrold Nadler, who is the Democratic chairman of the House Judiciary Committee, said the president could either attend or “stop complaining about the process”. “I hope that he chooses to participate in the inquiry, directly or through counsel, as other presidents have done before him,” he said.

In case Trump opts to attend the proceedings, he will be able to question the witnesses. The president was given a deadline of December 1 to confirm whether he will be present at the hearing, and provide details of his counsel if he attended.

Nadler’s letter also explained what the inquiry hoped to achieve through the proceedings. “We expect to discuss the constitutional framework through which the House may analyse the evidence gathered in the present inquiry,” the letter said, according to Independent. “We will also discuss whether your alleged actions warrant the Houses’ exercising the authority to adopt articles of impeachment.”

The impeachment inquiry focuses on a July 25 phone conversation between the US president and Ukrainian President Volodymyr Zelensky. Trump had asked his Ukrainian counterpart to investigate Joe Biden, who is currently running against Trump as a Democratic candidate in the presidential elections slated for next year. Trump also asked for Biden’s son Hunter Biden, who had served as a director for Ukrainian energy company Burisma, to be investigated.

The inquiry will look into whether the president used the threat of withholding US military assistance to force Ukraine into investigating the Bidens. The Trump administration has repeatedly refused to cooperate with the impeachment inquiry as well as other Democratic-led investigations. It has also directed current and former officials to defy subpoenas for documents and testimony.

A federal judge on Monday ruled that former White House counsel Don McGahn must testify in the impeachment inquiry against President Donald Trump, rejecting the administration’s claims of immunity for officials by declaring that “no one is above the law”. McGahn was named an important figure in the 448-page report completed in March by former Special Counsel Robert Mueller that detailed Russian interference in the 2016 US presidential election.