President Donald Trump lashed out in a series of tweets Friday morning amid a firestorm over the abrupt firing of FBI Director James Comey. Meanwhile, his lawyers say his past 10 tax returns show no income from Russian sources.

WASHINGTON President Donald Trump lashed out in a series of tweets Friday morning amid a firestorm over the abrupt firing of FBI Director James Comey, defending the shifting narrative and timeline his administration has offered for the decision.

He questioned whether his administration should cancel all future press briefings and, instead, replace them with written responses to questions, "for the sake of accuracy."

The president's advisers said this week that Trump fired Comey on Tuesday in response to a recommendation by Deputy Attorney General Rod Rosenstein. Later, however, they said that Trump had planned to fire Comey regardless.

The president tweeted, "As a very active President with lots of things happening, it is not possible for my surrogates to stand at podium with perfect accuracy!"

He added, "Maybe the best thing to do would be to cancel all future 'press briefings' and hand out written responses for the sake of accuracy???"

The decision to fire Comey amid an ongoing FBI investigation into ties between the Russian government and members of Trump's 2016 campaign has raised concerns that Trump was trying to undermine a probe that could threaten his presidency.

White House spokeswoman Sarah Huckabee Sanders insisted the information she and her colleagues offered was consistent. "It was a quick-moving process," she said. "We took the information we had as best we have it and got it out to the American people as quickly as we could."

White House spokesman Sean Spicer said Tuesday that Rosenstein drafted the memo raising concerns about Comey on his own accord. The next day, Sanders said the president asked Rosenstein to put his concerns in writing.

The White House also changed its narrative about whether the president had decided to fire Comey based on the recommendations by Rosenstein and Attorney General Jeff Sessions.

At first, the administration said that Rosenstein "made the recommendation, the president made a swift and decisive action and let Comey go."

Later, the president and his advisers said Trump had planned to fire Comey since taking office.

The White House also shifted its stance on whether Comey's termination had anything to do with the Russia investigation, at first saying it was not linked. Later, Sanders said, "We want this to come to its conclusion, we want it to come to its conclusion with integrity."

"And we think that we've actually, by removing Director Comey, taken steps to make that happen," she added.

Earlier Friday, Trump reiterated his view that reports about collusion with the Russian government by members of his 2016 campaign are "fabricated."

The president tweeted, "Again, the story that there was collusion between the Russians & Trump campaign was fabricated by Dems as an excuse for losing the election."

"The Fake Media is working overtime today!" he added.

Trump's lawyers say a review of his last 10 years of tax returns do not reflect "any income of any type from Russian sources," with some exceptions.

The lawyers did not release copies of Trump's tax returns so The Associated Press cannot independently verify their conclusions.

The letter says there is no equity investment by Russians in entities controlled by Trump or debt owed by Trump to Russian lenders. It does reflect income from the 2013 Miss Universe pageant held in Moscow and a property sold to a Russian billionaire in 2008 for $95 million.

The White House says Trump asked his lawyers for a letter following a request from Republican Sen. Lindsey Graham of South Carolina, who heads one of the congressional committees investigating Russia's interference in last year's election.