WASHINGTON -- The White House said President Donald Trump had considered firing the director of the FBI "since the day he was elected," as the administration sought further to explain the abrupt decision that has stunned Washington.
Spokeswoman Sarah Sanders told reporters on May 10 that Trump had lost confidence in Director James Comey as a result of "missteps and mistakes."
Comey, whom Trump had publicly praised as recently as last month, was overseeing the criminal investigations into ties between Trump associates and Russian officials -- something that has shadowed Trump since his election in November.
Comey has not made any public statement since the May 9 announcement that he was being fired.
The two top lawmakers on the Senate Intelligence Committee, which is investigating alleged Russian meddling in last year's presidential election, said they had asked Comey to testify before the committee next week.
In his May 9 announcement, Trump explained the firing, saying that Comey had mishandled an investigation into Democratic presidential candidate Hillary Clinton's e-mails. Clinton's use of a private e-mail server was a major issue during the election campaign, and Comey spoke publicly about it in the final days before the November 8 election.
Early on May 10, after a White House meeting with Russia's foreign minister, Trump further explained his decision.
"He wasn’t doing a good job, very simply. He wasn’t doing a good job," Trump told reporters.
It was the second time in U.S. history that an FBI director had been dismissed. President Bill Clinton fired William Sessions amid allegations of ethical lapses in 1993.
Vice President Mike Pence also defended the move, saying that Trump had made "the right decision at the right time."
Pence said Comey's firing was unrelated to the Russia probe.
He told reporters that Trump was in the process of evaluating candidates with "great integrity and great experience" to take over the FBI.
Earlier on May 10, Trump said in a series of posts to Twitter that Comey "will be replaced by someone who will do a far better job, bringing back the spirit and prestige of the FBI."
"Comey lost the confidence of almost everyone in Washington, Republican and Democrat alike. When things calm down, they will be thanking me," Trump added on Twitter.
Justice Department officials said Comey's deputy, Andrew McCabe, will serve as acting FBI director. McCabe was tentatively scheduled to speak before another Senate committee on May 11, but it was unclear if that appearance would go forward.
The firing shocked many in Washington and led to accusations from Democrats and others that the White House was trying to undermine the FBI probe involving Russia.
At least three different congressional committees, including the Senate intelligence panel, are also looking into Russian meddling in U.S. politics.
The Senate's top Republican, Mitch McConnell, said he did not support appointing an independent investigator, saying it would impede the current probes under way.
"Today we'll no doubt hear calls for a new investigation, which could only serve to impede the current work being done," McConnell said.
He didn't give his own view on Trump's decision to fire Comey. But he noted that Democrats had repeatedly criticized Comey in the past and had called for his removal.
WATCH: Senate Democratic Leader Blasts Firing Of FBI Chief
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Senate Democratic Leader Blasts Firing Of FBI Chief
Following McConnell on the floor, the body's top Democrat, Chuck Schumer, did call for a special prosecutor.
Schumer also asked that Attorney General Jeff Sessions and his deputy appear before the Senate to answer questions about the firing.
In one of the strongest Republican reactions, Richard Burr, chairman of the Senate Intelligence Committee, said he was “troubled" by the firing.
"His dismissal further confuses an already difficult investigation by the committee," he said.
"This is the biggest evidence to date of why we need an independent commission to investigate Russia’s interference in our election," Ben Cardin, the top Democrat on the Senate Foreign Relations Committee, said on May 9 in a statement.
Meanwhile, The New York Times reported that just days before his dismissal, Comey had requested additional funding and personnel for the agency's probe into alleged Russian interference.
Comey had asked Deputy Attorney General Rod Rosenstein last week for a significant boost in resources and later briefed U.S. lawmakers on the request, the newspaper said, citing three unnamed officials.
Russian Foreign Minister Sergei Lavrov, who met with Trump at the White House, sarcastically acknowledged Comey’s dismissal by saying, "Was he fired? You're kidding. You're kidding," as he posed for photographs with U.S. Secretary of State Rex Tillerson.
Earlier in the day, Kremlin spokesman Dmitry Peskov said Trump's decision was an "independent decision, which has nothing to do and should have nothing to do with Russia."
Peskov said he hoped the issue would not affect U.S.-Russian relations.
Trump called for better relations with Russia during the campaign in 2016, but since assuming office has followed a more conventional Republican line, strongly backing NATO's efforts to counter Russia's military buildup and aggression in Europe, from the Baltics to Ukraine and Georgia.