WASHINGTON (AP) - Former FBI Director James Comey says he thinks there's "certainly some evidence of obstruction of justice" in the actions of President Donald Trump.

Comey answered "possibly" when asked in an ABC News interview whether the president was attempting to obstruct justice when he asked Comey to end an FBI investigation into former White House national security adviser Michael Flynn.

Trump has denied that conversation, but Comey insisted that it definitely occurred.

He says there's "certainly some evidence of obstruction of justice," though he notes that he's just a witness in the case and not an investigator or prosecutor.

Comey is promoting a new book - and incurring Trump's wrath as he does. The president has called him a "liar and a leaker."