Twenty state attorneys general are calling on Deputy Attorney General Rod Rosenstein to appoint a special counsel in the federal investigation into Russian interference in the 2016 election.

In a letter to Rosenstein, who recommended the firing of James Comey as FBI director, the group of attorneys general argue that the public deserves a thorough investigation that examines the extent of Russian meddling, any possible collusion between Trump campaign officials and Russia and any possible cover-up.

“Only the appointment of an independent special counsel….with full powers and resources, can begin to restore public confidence. We urge you to appoint a special counsel immediately,” they said.

The letter is signed by attorneys general from the following states: Massachusetts, California, Connecticut, Hawaii, Iowa, Illinois, Maine, Maryland, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Virginia, Vermont, Washington, Delaware, Minnesota and Washington, D.C.

Comey’s dismissal ordered by President Trump, they said, in the middle of the Russia investigation is “a violation of the public trust.”

A slew of Democrats are calling for a special prosecutor or special counsel to be appointed, but no Republicans appear to be on board with that move. Congress, however, has no say in whether there would be one. Rosenstein, who was recently confirmed by the Senate, would have that power since Attorney General Jeff Sessions recused himself from the probe.

On Wednesday, Senate Minority Leader Chuck Schumer, D-New York, laid out Democrats’ demands following Comey’s ouster, one of which is having someone other than Rosenstein to appoint a special prosecutor. He said that responsibility should go to the highest-ranking civil servant at the Department of Justice.

This story originally appeared on CBS News.