The comments represented an extraordinary moment in the investigation, which centers in part on the administration’s contacts with Russian officials: A day after firing the man leading that inquiry, Mr. Trump disparaged him — to Russian officials. 
 
 The White House document that contained Mr. Trump’s comments was based on notes taken from inside the Oval Office and has been circulated as the official account of the meeting. One official read quotations to The Times, and a second official confirmed the broad outlines of the discussion. 
 
 Sean Spicer, the White House press secretary, did not dispute the account. 
 
 In a statement, he said that Mr. Comey had behaved politically and put unnecessary pressure on the president’s ability to conduct diplomacy with Russia on matters such as Syria, Ukraine and the Islamic State. 
 
 “By grandstanding and politicizing the investigation into Russia’s actions, James Comey created unnecessary pressure on our ability to engage and negotiate with Russia,” Mr. Spicer said. “The investigation would have always continued, and obviously, the termination of Comey would not have ended it. Once again, the real story is that our national security has been undermined by the leaking of private and highly classified conversations.” 
 
 The day after firing Mr. Comey, Mr. Trump hosted Russia’s foreign minister, Sergey V. Lavrov, in the Oval Office, along with the Russian ambassador to the United States, Sergey I. Kislyak. The meeting ignited controversy this week when it was revealed that Mr. Trump had disclosed intelligence from an Israeli counterterrorism operation. 
 
 A third government official briefed on the meeting defended the president, saying that Mr. Trump, whose discursive speaking style has hindered him in office, was using a negotiating tactic when he told Mr. Lavrov about the “pressure” he was under. The idea, the official suggested, was to create a sense of obligation with Russian officials and to coax concessions out of Mr. Lavrov — on Syria, Ukraine and other issues — by saying that Russian meddling in last year’s election had created enormous political problems for Mr. Trump. ||||| The law enforcement investigation into possible coordination between Russia and the Trump campaign has identified a current White House official as a significant person of interest, showing that the probe is reaching into the highest levels of government, according to people familiar with the matter. 
 
 The senior White House adviser under scrutiny by investigators is someone close to the president, according to these people, who would not further identify the official. 
 
 The revelation comes as the investigation appears to be entering a more overtly active phase, with investigators shifting from work that has remained largely hidden from the public to conducting interviews and using a grand jury to issue subpoenas. The intensity of the probe is expected to accelerate in the coming weeks, the people said. 
 
 The sources emphasized that investigators remain keenly interested in people who previously wielded influence in the Trump campaign and administration but are no longer part of it, including former national security adviser Michael Flynn and former campaign chairman Paul Manafort. 
 
 Flynn resigned in February after disclosures that he had lied to administration officials about his contacts with Russian Ambassador Sergey Kislyak. Current administration officials who have acknowledged contacts with Russian officials include President Trump’s son-in-law, Jared Kushner, as well as Attorney General Jeff Sessions and Secretary of State Rex Tillerson. 
 
 (Peter Stevenson,Jason Aldag,Whitney Leaming/The Washington Post) 
 
 [Graphic: What we know so far about Team Trump’s ties to Russian interests] 
 
 People familiar with the investigation said the intensifying effort does not mean criminal charges are near, or that any such charges will result. Earlier this week, Deputy Attorney General Rod J. Rosenstein appointed former FBI director Robert S. Mueller III to serve as special counsel and lead the investigation into Russian meddling. 
 
 It is unclear exactly how Mueller’s leadership will affect the direction of the probe, and he is already bringing in new people to work on the team. Those familiar with the case said its significance had increased before Mueller’s appointment. 
 
 Although the case began quietly last July as an effort to determine whether any Trump associates coordinated with Russian operatives to meddle in the presidential election campaign, the investigative work now being done by the FBI also includes determining whether any financial crimes were committed by people close to the president. The people familiar with the matter said the probe has sharpened into something more fraught for the White House, the FBI and the Justice Department — particularly because of the public steps investigators know they now need to take, the people said. 
 
 When subpoenas are issued or interviews are requested, it is possible the people being asked to talk or provide documents will reveal publicly what they were asked about. 
 
 A small group of lawmakers known as the Gang of Eight was notified of the change in tempo and focus in the investigation at a classified briefing Wednesday evening, the people familiar with the matter said. Then-FBI Director James B. Comey publicly confirmed the existence of the investigation in March. 
 
 Justice Department spokeswoman Sarah Isgur Flores said, “I can’t confirm or deny the existence or nonexistence of investigations or targets of investigations.” An FBI spokesman declined to comment. 
 
 White House spokesman Sean Spicer said, “As the president has stated before, a thorough investigation will confirm that there was no collusion between the campaign and any foreign entity.’’ 
 
 While there has been a loud public debate in recent days over the question of whether the president might have attempted to obstruct justice in his private dealings with Comey, whom Trump fired last week, people familiar with the matter said investigators on the case are more focused on Russian influence operations and possible financial crimes. 
 
 The FBI’s investigation seeks to determine whether and to what extent Trump associates were in contact with Kremlin operatives, what business dealings they might have had in Russia, and whether they in any way facilitated the hacking and publishing of emails from the Democratic National Committee and Hillary Clinton’s campaign chairman, John Podesta, during the presidential campaign. Several congressional committees are also investigating, though their probes could not produce criminal charges. 
 
 [Appointment of Mueller could complicate other probes into alleged Russian meddling] 
 
 A grand jury in Alexandria, Va., recently issued a subpoena for records related to Flynn’s business, the Flynn Intel Group, which was paid more than $500,000 by a company owned by a Turkish American businessman close to top Turkish officials, according to people familiar with the matter. 
 
 The Flynn Intel Group was paid for research on Fethullah Gulen, a cleric who Turkey’s current president believes was responsible for a coup attempt last summer. Flynn retroactively registered with the Justice Department in March as a paid foreign agent for Turkish interests. 
 
 Separately from the probe now run by Mueller, Flynn is being investigated by the Pentagon’s top watchdog for his foreign payments. Flynn also received $45,000 to appear in 2015 with Russian President Vladimir Putin at a dinner for RT, a Kremlin-controlled media organization. 
 
 Flynn discussed U.S. sanctions against Russia with Russia’s ambassador to the United States during the month before Trump took office, and he withheld that fact from the vice president. That prompted then-acting attorney general Sally Yates to warn the White House’s top lawyer that Flynn might be susceptible to blackmail. Flynn stepped down after The Washington Post reported on the contents of the call. 
 
 The president has nonetheless seemed to defend his former adviser. A memo by Comey alleged that Trump asked that the probe into Flynn be shut down. 
 
 [Notes made by FBI Director Comey say Trump pressured him to end Flynn probe] 
 
 The White House also has acknowledged that Kushner met with Kislyak, the Russian ambassador to the United States, in late November. Kushner also has acknowledged that he met with the head of a Russian development bank, Vnesheconombank, which has been under U.S. sanctions since July 2014. The president’s son-in-law initially omitted contacts with foreign leaders from a national security questionnaire, though his lawyer has said publicly he submitted the form prematurely and informed the FBI soon after that he would provide an update. 
 
 Vnesheconombank handles development for the state, and in early 2015, a man purporting to be one of its New York-based employees was arrested and accused of being an unregistered spy. 
 
 That man — Evgeny Buryakov — ultimately pleaded guilty and was eventually deported. He had been in contact with former Trump adviser Carter Page, though Page has said he shared only “basic immaterial information and publicly available research documents” with the Russian. Page was the subject of a secret warrant last year issued by the Foreign Intelligence Surveillance Court, based on suspicions he might have been acting as an agent of the Russian government, according to people familiar with the matter. Page has denied any wrongdoing, and accused the government of violating his civil rights. 
 
 Ellen Nakashima and Ashley Parker contributed to this report. 
 
 Read more: 
 
 What’s next in the Russia investigation? The week’s biggest bombshells. 
 
 White House offers shifting explanations of Trump’s disclosures to Russians 
 
 Trump revealed highly classified information to Russian foreign minister and ambassador
– President Trump told Russian officials that firing James Comey took a "great pressure" off him in regard to the ongoing investigation into his campaign's possible collusion with Russia, the New York Times reports. He also told Russian officials the former FBI director was "crazy, a real nut job." The quotes come from a document summarizing Trump's May 10 meeting with Russian foreign minister Sergey Lavrov and ambassador Sergey Kislyak in the Oval Office. The document is being treated as the official account of the meeting, and Sean Spicer didn't dispute its contents. It appears to be another incidence of Trump claiming he fired Comey because of the Russian investigation, contradicting the official reason given by the White House. One official says Trump was attempting a negotiating tactic on the Russians, making them feel bad about the political pressure they caused for him. Meanwhile, the Washington Post reports the investigation into possible collusion between Russia and the Trump campaign now includes a current White House official as a significant person of interest. Sources close to the investigation say it's now looking at a senior White House adviser close to the president. While the official isn't being identified, current White House officials that have admitted to having contact with Russian officials include Jared Kushner, Jeff Sessions, and Rex Tillerson. While the investigation is ramping up to interviews and subpoenas, sources with knowledge of it say that doesn't mean criminal charges are a given.