James Clapper, the US intelligence chief, resigns

He told the House Intelligence Committee that "it felt pretty good".

The 75-year-old top American spy had been expected to step aside, as President-elect Donald Trump prepares to appoint his own officials.

Analysts believe that he is sending a signal to the Trump administration that they must now speed up the transition.

Mr Trump has denied that his transition team is in turmoil, despite having only filled two postings so far.

One of his close advisers, Kellyanne Conway, told reporters at Trump Tower in New York that announcements would be made before or after Thanksgiving, which is one week away.

Mr Clapper will remain in post until President Barack Obama leaves office.

"I submitted my letter of resignation last night which felt pretty good. I've got 64 days left," he said.

Committee members jokingly asked him to stay for four more years.

Mr Clapper has authority over 17 different agencies including the Central Intelligence Agency (CIA), the Drug Enforcement Agency (DEA), and the (Federal Bureau of Investigation (FBI).

More than 107,000 employees report to him with a combined budget of over $52 billion (£41.8 billion).

• Was Trump's election democratic?
• The people around Donald Trump
• The Trump resistance movement builds
• Trump elected - full report

In a profile published by Wired magazine only hours before his announcement, he said that he never questioned the morality of his profession.

In his role, he has often been in the position of defending the National Security Agency (NSA), just one of the covert agencies that his office oversees.

Its image was badly damaged after Edward Snowden revealed how they collect information on American citizens.

During a 2013 congressional hearing, Mr Clapper was asked: "Does the NSA collect any type of data at all on millions, or hundreds of millions, of Americans?"

"No, sir," Mr Clapper replied.

"It does not?" the incredulous senator responded.

"Not wittingly," Clapper said. "There are cases where they could inadvertently, perhaps, collect, but not wittingly."

On Thursday, he was asked if Mr Trump will open up a rapprochement with Russia's President Vladimir Putin, but answered that he does not predict a "significant change in Russian behaviour".

Mr Clapper has served in the job for six years after previously working for the US Air Force and the Defence Intelligence Agency.