Eighteen US state Attorneys General have urged the new Acting Attorney General Matthew Whitaker to recuse himself from an ongoing investigation on the alleged Russian meddling in the 2016 presidential elections.
In a letter on Thursday, the Attorneys General said that Special Counsel Robert Mueller's probe "must proceed free from interference", reports Xinhua news agency.
"Because a reasonable person could question your impartiality in the matter, your recusal is necessary to maintain public trust in the integrity of the investigation and to protect the essential and longstanding independence of the Department you have been chosen to lead, on an acting basis," the letter said.
Whitaker, who was the chief of staff at the Department of Justice, replaced Jeff Sessions who resigned on Wednesday as Attorney General.
As Mueller's new boss, Whitaker is expected to take charge of oversight over the ongoing Russia investigation, including approval of budget decisions and subpoenas.
When posting the joint letter on Twitter, Maura Healey, Attorney General of Massachusetts, said that Whitaker's "hostility to the Special Counsel's investigation disqualifies him from overseeing Robort Muller".
Whitaker was known to be sceptical about Mueller's probe on alleged Russian interference and President Donald Trump's connection with Russia in the 2016 election.
Russia has denied any involvement in the elections.
The letter was signed by the Attorneys general of Massachusetts, New York, Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Minnesota, New Jersey, California, North Carolina, Oregon, Vermont, Rhode Island, Washington, Virginia, New Mexico and Maryland.