Image copyright Reuters Image caption Christopher Wray served in the Bush administration 2003-05

US President Donald Trump has said he is nominating lawyer Christopher Wray to become the new director of the Federal Bureau of Investigation (FBI).

The post has been empty for the past month after Mr Trump fired James Comey from the key law enforcement role.

Mr Wray served under George W Bush as an assistant attorney general from 2003 to 2005.

Mr Trump described Mr Wray as "a man of impeccable credentials" in a tweet on Wednesday.

The appointment will have to be approved by the Senate.

Image copyright Twitter / Donald Trump Image caption President Trump tweeted the announcement

The Yale Law School graduate is currently a partner at King & Spalding law firm in its offices in Washington DC and Atlanta.

While at the Department of Justice (DOJ), he headed the criminal division, overseeing major corporate fraud scandals, including the crisis at energy giant Enron.

"Mr Wray was also integral to the DOJ's response to the 9/11 attacks and played a key role in the oversight of legal and operational actions in the continuing war on terrorism," says the King & Spalding website.

He was also a lawyer representing New Jersey Governor - and Trump ally - Chris Christie after a 2013 scandal dubbed Bridgegate.

Two of Mr Christie's former aides were convicted of plotting to close lanes of traffic on a New York City bridge as revenge against a Democratic mayor who did not endorse the governor. Mr Christie denied any knowledge of the plan and was not charged.

"I think that the president certainly would not be making a mistake if he asked Chris Wray to be FBI director," Mr Christie said last week, according to news site NorthJersey.com.

The New York Times described Mr Wray as a "safe, mainstream pick" after the president had said he might have opted to appoint a politician for the role. The post has historically been non-political.

Analysis: Tara McKelvey, BBC News, Washington

Christopher Wray seems tough enough to be FBI director - he's been a federal prosecutor and worked for the justice department after the 2001 terror attacks. He also has two degrees from Yale (undergraduate and law).

Most importantly, though, the president trusts him. Democrats on the Hill, however, said they were not sure about Mr Wray. They said they were still learning about his background.

They're also worried about the timing of the announcement, which some see as a way to distract people from the James Comey hearing.

Christopher Wray seems like a strong candidate but many Democrats have been unhappy with the way the president has treated Mr Comey and the bureau - and could slow down Mr Wray's appointment to get their message across.

President Trump's nomination decision comes the day before Mr Comey is set to testify before the Senate intelligence committee.

Image copyright Reuters Image caption James Comey,

He is expected to be asked about private discussions with Mr Trump regarding the investigation into alleged links between the president's administration and Russia.

He will give a public testimony, which will be broadcast on TV and online, and he will also answer "sensitive" questions from senators in a private hearing.

"I wish him luck," Mr Trump said of Mr Comey, as he met Republicans on Wednesday.

US media has reported that Mr Comey told Attorney General Jeff Sessions that he did not want to be left alone with the president when they met.

The Washington Post has also reported that the president had asked Dan Coats, his director of national intelligence, to try to persuade the FBI to back off their investigation into his former national security adviser, Michael Flynn, who resigned in February following concern about his Kremlin contacts.

Mr Coats will give evidence to the Senate Intelligence Committee hearing later on Wednesday.

Mr Comey was fired in early May. It was only the second time the head of the FBI had been dismissed.

The White House first said the dismissal was prompted by Mr Comey's handling of the inquiry into defeated Democratic presidential candidate Hillary Clinton's emails.

But Mr Trump subsequently said Mr Comey "wasn't doing a good job" and was "a showboat".