The President made the remark while speaking to pool reporters in the Oval Office. He was meeting
with former Secretary of State Henry Kissinger after having met earlier in the day with Russian Foreign Minister Sergey Lavrov and Russian Ambassador to the US Sergey Kislyak.
Asked if Comey's firing affected the meeting with the Russians, Trump replied, "not at all."
Kislyak has been a central figure in the controversy over Trump's campaign ties to Russia, as then-national security adviser Michael Flynn was fired after it emerged that he had misrepresented conversations with Kislyak to others in the White House.
Trump also spoke about Syria during his Oval Office comments: "We're talking about Syria and I think we're going to do very well with respect to Syria. I think things are happening that are really, really, really positive. We're going to stop the killing and the death."
Shortly before Trump's comments became public, Vice President Mike Pence praised the Comey firing
on Capitol Hill, telling reporters it was the "right move at the right time" and reiterating the administration's position that there is "no evidence of collusion between our campaign and any Russian officials."
Trump also tweeted several times about the Comey firing Wednesday morning, saying the move will be seen in a better light after the furious controversy dies down.
At one point in a series of tweets, Trump said his dismissal of Comey -- who came under withering criticism from both Democrats and Republicans for his handling of the Hillary Clinton email investigation -- would be validated after "things calm down."
"Comey lost the confidence of almost everyone in Washington, Republican and Democrat alike. When things calm down, they will be thanking me!" Trump tweeted.
He led off the tweetstorm with criticism of Democrats, who have loudly called for a special prosecutor to look into alleged ties between his campaign and Russia. Democrats -- and some Republicans -- were quick on Tuesday to claim that Trump was ridding himself of an investigator who was delving too deeply into ties between his associates and Russia.
"The Democrats have said some of the worst things about James Comey, including the fact that he should be fired, but now they play so sad!" Trump wrote.
Trump then said Comey will be replaced by "someone who will do a far better job."
The President also tweeted out a link shared by Drudge Report on "10 scandals" under Comey's watch.
Senior White House officials appeared to have badly misjudged the impact of Trump's sudden move. A source with knowledge of discussions inside the White House told CNN's Dana Bash
that the thinking was that because Democrats were saying precisely what Deputy Attorney General Rod Rosenstein said in a letter explaining the grounds for Comey's dismissal, there would be no backlash.
What was not thought through, apparently, was an explanation of why Comey was fired now, at a time when critics would immediately conclude it was because of the Russia probe.