U.S. President Donald Trump | Brendan Smialowski/AFP via Getty Images Democrats escalate talk of Trump impeachment Prior to FBI director’s firing, heated rhetoric had been minimal.

As the White House descended into turmoil over the firing of FBI Director James Comey, congressional Democrats sharply escalated their rhetoric over President Donald Trump's impeachment and even imprisonment.

In late-night tweets Thursday, several Democrats strongly suggested they believe Trump should face impeachment and perhaps criminal charges for firing Comey in the midst of an FBI investigation into the Trump campaign's dealings with Russia.

"Evidence of Trump's effort to obstruct justice continues to emerge. Lock HIM up?" tweeted Rep. Hakeem Jeffries (D-N.Y.) shortly after midnight.

California Democratic Rep. Jared Huffman suggested Trump could be impeached immediately if Republicans would get on board.

"Impeachment will happen if handful of Republicans in Congress join Dems to put country above party. Or in 2019 after Dems win the House," he tweeted from his campaign account shortly before 3 a.m. Eastern.

Until this week, most Democrats avoided that type of heated rhetoric about Trump, brushing off activists' calls for Trump's impeachment as premature. Only Rep. Maxine Waters (D-Calif.) had broached the subject early in Trump's term, suggesting he was on a path to impeachment. On Thursday, Waters suggested Trump may have broken the law.

"I think he can be looked at and perhaps even charged with obstruction of justice," she said on MSNBC, tweeting out the snippet.

Democratic leaders have previously downplayed early talk of Trump's impeachment.