Washington, Jul 18 (IANS): Former FBI Director James Comey, who was fired by President Donald Trump last year, has urged "all who believe in this country's values" to vote for Democrats in the upcoming mid-term elections.

In a tweet on Tuesday evening, Comey called the Republican-held Congress "incapable of fulfilling the Founders' design".

"This Republican Congress has proven incapable of fulfilling the Founders' design that 'Ambition must ... counteract ambition.' All who believe in this country's values must vote for Democrats this fall. Policy differences don't matter right now. History has its eyes on us," he wrote.

Comey also spoke out Monday against Trump's comments at his joint news conference with Russian President Vladimir Putin in Finland.

"This was the day an American President stood on foreign soil next to a murderous lying thug and refused to back his own country. Patriots need to stand up and reject the behaviour of this President," he was quoted as saying by CNN.

Comey served under both Republican and Democratic administrations, but during 2016 testimony before Congress he noted he had been registered as a Republican most of his life, adding that he was no longer registered.

He has been vocal about his frustration with the Republican Party before and in April he said he could no longer "be associated with it".

"The Republican Party has left me and many others. I need no better evidence than their new website -- which I think is 'Lyin Comey,' maybe? -- attacking me. I just think they've lost their way, and I can't be associated with it," Comey told ABC News' "Start Here" podcast at the time.