U.S. Sen. Angus King of Maine raised impeachment of President Donald Trump as a possibility for the first time on Tuesday after a report said the president had told the FBI director he fired last week to drop an investigation into alleged Russian election tampering.

King, an independent who caucuses with Democrats, answered a question from CNN’s Wolf Blitzer on whether the country “might be getting closer and closer to the possibility of the beginning of yet another impeachment process” if The New York Times’ report on James Comey is true.

“I have to say yes simply because obstruction of justice is such a serious offense, and I say it with sadness and reluctance,” King said. “This is not something that I have advocated for. The word [impeachment] has not passed my lips in this whole tumultuous three or four months.”

The Times first reported on Tuesday that the Republican president asked the FBI to drop its investigation into former National Security Adviser Michael Flynn for possible coordination between Russian officials and Trump associates and urged Comey to instead pursue investigations into leaks to the media.

The White House issued a denial of the Times report on Tuesday, saying the president “has never asked Mr. Comey or anyone else to end an investigation, including any investigation involving General Flynn.”

In a conference call with Maine reporters, King, a member of the Senate Intelligence Committee, said he learned on Tuesday that Comey “is planning to testify in public” and he’ll likely do so “in the recently near future.” However, he said he didn’t know when or whether it would be before his committee or another one.

U.S. Sen. Susan Collins, a Maine Republican who is also on the intelligence committee, joined a chorus of voices calling on Comey to testify. The House Oversight Committee has also requested the memo from Comey cited by the Times.

Collins spokeswoman Annie Clark said Maine’s senior senator “believes the allegations made in the New York Times are serious and warrant further investigation” and “it is going to be necessary to see the actual memo and to hear from Mr. Comey directly so that he can give context to the conversation.”

King called Comey a “by-the-book guy,” saying Congress must “get to the facts of this situation” and verify any conversation between Trump and Comey. To do that, he said, “we need to hear from Director Comey.”

“I’m not prepared to comment on the credibility of the White House. I would say that Jim Comey has a high level of credibility,” King said. “But that doesn’t mean that there isn’t another side to the story.”

Michael Shepherd joined the Bangor Daily News in 2015 after time at the Kennebec Journal. He lives in Augusta, graduated from the University of Maine in 2012 and has a master's degree from the University...