A group of House Democrats wrote to Speaker Paul Ryan, R-Wis., on Tuesday, urging him to issue a statement in support of special counsel Robert Mueller and explain what "actions" he would take if President Trump fires him or disrupts his investigation.

The letter claims Trump has already dismissed FBI Director James Comey in order to hamper the federal investigation into possible collusion between the Trump campaign and Russia. With the indictment of former Trump campaign manager Paul Manafort, the Democrats say Trump could attempt a similar sabotage of the inquiry.

“We strongly believe that firing the Special Counsel would represent a brazen attempt by the President to shield himself and his associates from the legal consequences of the Mueller investigation. It would also provide yet more convincing evidence that his campaign was guilty of illegally coordinating with a foreign power in order to influence the results of a presidential election,” the lawmakers wrote. “We therefore urge you to put partisan politics aside and issue a statement expressing your support for Mueller and clarifying what actions you will take in the event that he is dismissed or his investigation is disrupted.”

Ryan has spoken favorably of Mueller in the past, saying in July that Mueller is "anything but" partisan. In June he said Trump should "let Robert Mueller do his job."

Still, some of the Trump faithful, like Steve Bannon, have reportedly urged Trump to restrain Mueller's operation. Meanwhile, some, like Fox News' Sean Hannity, have said Mueller should resign.

The letter, signed by Reps. Jamie Raskin, D-Md.; Ted Lieu, D-Calif.; Brendan Boyle, D-Pa.; Pramila Jayapal, D-Was.; Brenda Lawrence, D-Mich.; and Ruben Gallego, D-Ariz., also said the Washington Post report over the summer that Trump is being investigated for possible obstruction of justice may also influence him in trying to do away with Mueller.

Trump has not said he plans to remove Mueller from his role as special counsel, but that has not stopped bipartisan legislation that would protect Mueller if he did try.

In the letter Tuesday, the Democrats said Trump and his administration have repeatedly tried to "discredit the work of Mueller and his expert legal team" by calling the investigation such names as a "witch hunt" and "hoax," while also calling into question its cost.

Mueller, a former FBI director, was appointed special counsel by Deputy Attorney General Rod Rosenstein after Attorney General Jeff Sessions recused himself from any Russia-related probes. Trump said over the summer that he wouldn't have picked Sessions to be his attorney general had he known Sessions would recuse himself.