Most Americans say President Donald Trump's firing of FBI Director James Comey was inappropriate and diminishes their confidence in a fair investigation of potential ties between his campaign and Russians who interfered with the 2016 election.

Those are the findings of a new NBC News/Survey Monkey online poll conducted May 10-11 after Trump's abrupt action. The survey of 3,746 likely voters carries a margin for error of 2.5 percentage points.

Only 38 percent of Americans call the president's action appropriate, while 54 percent call it not appropriate. Those numbers almost perfectly track Trump's latest approval numbers (38 percent to 55 percent) in the Gallup tracking poll. Similarly, 55 percent said Trump's move makes them less confident that the Russia investigation will be conducted fairly, while 36 percent say it makes them more confident.

A 46 percent plurality said Trump acted because of Comey's handling of the Russia investigation — an explanation the White House insists is not true. Just 24 percent ascribed the decision to Comey's handling of the Hillary Clinton email investigation, which the White House initially cited in explaining the president's motivation. Some 22 percent said it was something else.

The poll also makes clear that Americans do not share Trump's view that the subject represents "fake news." A 54 percent majority call the allegations involving Russians and the Trump campaign "a serious issue," while 40 percent call it "more of a distraction."