US spy chief steps down ahead of Trump presidency

US spy chief James Clapper has announced his resignation after six years serving as the director of national intelligence.

His departure from the post will be effective as of Jan. 20, the same day that outgoing Democrat president Barack Obama will step aside for his Republican replacement Donald Trump.

The 75-year-old former three-star US Air Force general, who during his tenure had a rocky relationship with Congress, had made no secret of his plan to resign at the end of Obama's term as president.

"I submitted my letter of resignation last night, which felt pretty good," Clapper told a US House of Representatives intelligence committee hearing on Thursday. "I've got 64 days left."

Clapper, who admitted to providing misleading testimony before the Senate Select Committee on Intelligence in March 2013 over government spying on millions of Americans, held his post during one of the most controversial periods in the history of US intelligence.

Months after Clapper told Senator Ron Wyden that the government did "not wittingly" spy on its citizens, former National Security Agency contractor Edward Snowden revealed that the government had indeed done so through a mass surveillance programme.

Clapper's office had also accused Russia of hacking US political operatives and individuals ahead of the Nov. 8 presidential election in an attempt to interfere with the country's democratic process.

While president-elect Donald Trump is yet to reveal Clapper's replacement, one of Clapper's former deputies, Robert Cardillo, has been tipped to take the post.

Former Defense Intelligence Agency head Lieutenant General Ronald Burgess and former House Intelligence Committee chair Pete Hoekstra are also likely candidates, sources told Reuters.

The new spy chief will be responsible for overseeing 17 US intelligence agencies and serve as the president's principal intelligence adviser and briefer.