US President Donald Trump announced on Twitter early Wednesday that he has selected former assistant attorney general Christopher Wray to lead the FBI, nearly a month after he controversially sacked former FBI Director James Comey.

Wray, now a partner at the law firm King & Spalding, was assistant attorney general between 2003 to 2005 during George W. Bush's tenure.

At that time he dealt with white collar crime and financial fraud, including leading the government task force investigation into energy giant Enron, according to the King & Spalding website.

While at King & Spalding, he represented Republican New Jersey Governor and former Trump campaign adviser Chris Christie in the "Bridgegate" scandal.  Christie was never charged, but two of his aides were convicted of plotting to close lanes on the George Washington Bridge to retaliate against a Democratic mayor who had refused to endorse Christie.

The announcement comes a day before James Comey is scheduled to testify before the Senate intelligence committee about allegations of Russian meddling in the US election and ties between the Trump campaign and the Kremlin.  

Comey is also expected to provide new details about the weeks leading up to his sacking on May 9. This includes allegations Trump asked the FBI director to drop an investigation into ties between Russia and former National Security Advisor Michael Flynn, who was fired for misleading the White House about conversations he had with Russia's ambassador in Washington.

The Justice Department appointed former FBI Director Robert Mueller as special counsel to lead the federal investigation following Comey's firing.

Wray's appointment will require confirmation at a special Senate hearing.

cw/msh (AP, dpa, Reuters)