Former FBI Director James Comey said the U.S. remains unprepared for another attack on its elections and faulted the attorney general for suggesting that the government was "spying" on Donald Trump's presidential campaign in 2016.

Echoing the findings of U.S. intelligence agencies, Comey said Russia intervened in the 2016 election to damage American democracy, undermine Democratic nominee Hillary Clinton and bolster Trump. Russian officials have denied the accusations. But Comey said Trump's "denial of a fundamental attack" on the U.S. means "we're inviting it to happen again with our president's silence."

The former FBI leader also said he was concerned by Attorney General William Barr's comments on Wednesday that he's starting his own inquiry into counterintelligence decisions that may have amounted to political espionage, including actions taken during the Russia probe in 2016.