(CNN) House Speaker Nancy Pelosi has tasked the Intelligence Committee to initially take the lead on the impeachment inquiry into President Donald Trump, telling her colleagues that the probe will for now be focused on allegations that he asked the leader of Ukraine to initiate an investigation that could have benefited his reelection, according to sources involved in the conversations.

Democrats for now don't plan to make the findings of special counsel Robert Mueller's report into potential obstruction of justice central to their impeachment push, which has been under review by the House Judiciary Committee, though Pelosi has told Democrats that the probe into those and other matters will continue.

The focus, however, will be squarely on the whistleblower allegations of wrongdoing by the President, as Democrats push to rapidly move forward on formal articles of impeachment as soon as this fall.

The decision to make the House Intelligence Committee initially take the lead provides more clarity over how Pelosi characterized the strategy earlier this week when she said the probe would be done by six committees under the "umbrella" of an impeachment inquiry. The initial description led to some confusion among members about how the investigation would take shape.

But Democratic leadership aides say that the other committees will continue their investigations -- and the focus could shift back to other elements of Trump's potential wrongdoing once the Ukraine probe plays out.

Yet broadening out the probe could also lose the support of some moderate Democrats who want the focus to stay trained on the Ukraine matter. They argue that raising concerns about Trump potentially weakening the country's security is a clearer message for voters back home.

In a news conference Thursday, Pelosi said that the whistleblower complaint is within the purview of the House Intelligence Committee and the timeline for the House's impeachment inquiry will be determined by that panel's investigation.

"The focus now is on this allegation," Pelosi said. "This is a coverup."

JUST WATCHED Pelosi: Trump's actions lift this to a whole new terrain Replay More Videos ... MUST WATCH Pelosi: Trump's actions lift this to a whole new terrain 01:39

Pelosi added, "When the committee finishes its work, and we have the work that has already been done by other chairs, there will be some determinations about how we proceed. But, I'm not going to go into that today."

Democrats have zeroed in on a July 25 phone call , in which Trump pushed for Ukrainian President Volodymyr Zelensky to investigate former Vice President Joe Biden, and his son, Hunter. Trump has said that the call was appropriate. There is no evidence of wrongdoing by either Joe or Hunter Biden.

A whistleblower's complaint released Thursday states that several White House officials were "deeply disturbed" by the Trump-Zelensky phone call and tried to "lock down" all records of it, especially the word-for-word transcript produced by the White House.

Democrats have spent months on the President's potential obstruction of justice from Mueller's probe of Russian interference in the 2016 election. But the allegations raised in the past week have motivated Pelosi to support an impeachment inquiry, removing the strongest impediment to Democrats in the House writing articles of impeachment.

The process is now expected to play out like this: The House Intelligence Committee will continue with its probe but the House Judiciary Committee will vote on the articles of impeachment before the full House takes up the matter.

Intelligence Chairman Adam Schiff, a California Democrat, told reporters on Thursday that his panel is "going to move as expeditiously as possible." The whistleblower complaint, he said, would provide a "roadmap" for the committee's push to interview witnesses and seek document requests over the matter.

Rep. Joaquin Castro, Democrat of Texas, told CNN he would hope the panel hear from "anybody" who was involved in moving the record of the phone call to a different electronic system used to store classified information.

House Judiciary Committee chairman Jerry Nadler, a New York Democrat, declined to comment when asked whether his panel would write articles of impeachment charging the President with abuse of power. But some Democrats on the Judiciary Committee told CNN they expected they would be based at least in part on a reconstruction of the call released by the White House and the whistleblower's complaint.

House Intelligence Committee Chairman Adam Schiff speaks at a news conference in April in Burbank, California. (Mario Tama/Getty Images)

"I believe the Ukraine issue will be part of an article of impeachment that shows abuse of power, abuse of office, the unpatriotic behavior of this President putting his own political gain above his oath — above our country," said Democratic Rep. Madeleine Dean of Pennsylvania. "This will definitely be an important article of impeachment."

"I think abuse of power is going to be a central part of the articles of impeachment," added Democratic Rep. Ted Deutch of Florida. "And that's on full display in the Intelligence Committee hearing this morning."

The intelligence community inspector general deemed the whistleblower's complaint to be "credible and urgent," a conclusion that set in motion acting Director of National Intelligence Joseph Maguire's appearance before Congress on Thursday.

Republicans pointed out that the whistleblower acknowledges in the complaint that he or she was not a "was not a direct witness to most of the events described."

"I think today was a circus that shouldn't have taken place," said Rep. John Ratcliffe, a Texas Republican. "I think the transcript speaks for itself. It's the best evidence of what happened, not a third-hand account from a whistleblower who wasn't there."

"Nowhere in there did I see the words 'have to,' 'must,' 'will,' — anything that exerted the kind of undue influence that the Democrats promised was going to be in there," Ratcliffe added.

Democrats noted that the whistleblower cited "more than half a dozen US officials" in the complaint and was deemed "credible" by the intelligence community inspector general.

"At the end of the day, what is alleged in this whistleblower complaint goes to the very heart of the President's oath of office," Schiff said.

JUST WATCHED Nunes to Maguire: They will use these words against you Replay More Videos ... MUST WATCH Nunes to Maguire: They will use these words against you 02:57

On Tuesday, Pelosi announced that the House would launch an "official impeachment inquiry." Pelosi mentioned that six committees — Intelligence, Judiciary, Foreign Affairs, Oversight, Financial Services and Ways and Means — would investigate under the "umbrella" of that inquiry. But there has been some confusion among House Democrats about how the inquiry will move forward.

When asked about Pelosi's announcement Tuesday setting up the "umbrella" of an impeachment inquiry, one Democratic congressman granted anonymity told CNN, "I don't know what that means exactly."

That lack of clarity could lead to some infighting among the committees. Rep. Gerry Connolly, a Virginia Democrat who serves on the Oversight panel, said that his committee has jurisdiction over "all" federal inspectors general.

"That's an angle we can assert in terms of jurisdiction," said Connolly. But when asked if it would, Connolly said, "We've got to work out who does what."

In a private meeting with House Democrats on Thursday, Pelosi made clear that the Intelligence Committee would be the point panel on the Ukraine investigation, given its jurisdiction and the narrow focus of its probe. Democratic Rep. Rosa DeLauro of Connecticut asked Pelosi if the five other committees should pause their work, according to a source.

Pelosi said that the other panels should continue, but made it clear the Intelligence Committee was in charge — a move that could quicken the pace of the impeachment inquiry. Some Democrats hope for a vote as soon as October.

"I think we are being thorough, but I think we are moving as expeditiously as possible as well," said Democratic Rep. Val Demings of Florida. "We are not wasting any time in terms of following the facts where they lead us."

House Judiciary Committee chairman Rep. Jerrold Nadler of New York speaks during a committee hearing earlier this month in Washington.

On their July call, Trump pressed the Ukrainian leader to investigate Biden's son Hunter, who sat on the board of an energy company, Burisma Holdings, whose owner was investigated by Ukrainian general prosecutor Viktor Shokin.

"There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the attorney general would be great," said Trump on the call, according to a reconstructed transcript released by the White House. "Biden went around bragging that he stopped the prosecution so if you can look into it ... It sounds horrible to me."

Trump also said he wanted his personal lawyer, Rudy Giuliani, and Attorney General Bill Barr to call Zelensky.

"We will get to the bottom of it," Trump said. "I'm sure you will figure it out. I heard the prosecutor was treated very badly and he was a very fair prosecutor so good luck with everything. Your economy is going to get better and better I predict."

While Biden -- when he was vice president -- and other Western leaders pushed for the dismissal of Shokin over lackluster anti-corruption efforts in 2016, Trump and Giuliani have claimed without evidence that Biden demanded Shokin's firing on behalf of his son. They cite Biden's threat to withhold $1 billion in aid to Ukraine if the country's leaders did not dismiss the prosecutor.

On August 12, a whistleblower expressed concerns to the intelligence community's inspector general Michael Atkinson about Trump's call with Zelensky. Atkinson deemed them credible and urgent and sent the complaint to Maguire.

Trump has denied that his call with Zelensky was improper. On Thursday, Trump called Schiff "Liddle'" and attacked other Democrats for starting "another witch hunt" in a tweet.

"A whistleblower with second hand information," asked Trump on Twitter. "Another Fake News Story! See what was said on the very nice, no pressure, call. Another Witch Hunt!"