WASHINGTON — Donald Trump Jr. told Senate investigators on Wednesday that he did not inform his father at the time about a June 2016 meeting with a Russian lawyer promising “dirt” on Hillary Clinton and that he was not kept abreast of negotiations over a proposed real estate project in Moscow, a person familiar with his testimony said.
The younger Mr. Trump, in roughly three hours of closed-door questioning in front of the Senate Intelligence Committee, said that he had nothing to correct from past statements that he had given that panel and other congressional bodies — despite claims by former Trump aides to the contrary.
Questioning appeared to focus on two of the most scrutinized issues of the 2016 presidential campaign: a meeting in Trump Tower in Manhattan between top Trump campaign officials and a Russian emissary, and the extensive efforts of the Trump Organization to secure a major development in Moscow even as Donald J. Trump was running for president.
“I don’t think I changed anything of what I said because there was nothing to change,” Donald Trump Jr. told reporters as he emerged from the session.
In the hearing room, where senators have been studying the Trump campaign’s ties to Russia’s election influence efforts, the younger Mr. Trump tried to undermine the two witnesses who had questioned his account, according to the person familiar with his remarks, who spoke on the condition of anonymity to discuss the private session. He said that those witnesses — Michael D. Cohen, his father’s former personal lawyer, and Rick Gates, a deputy campaign chairman — had both been indicted by the special counsel, Robert S. Mueller III. Details of the testimony were first reported by CNN.
Mr. Cohen told lawmakers in a public hearing this year that he believed that he had seen the younger Mr. Trump quietly alert his father to the meeting with the Russian lawyer, Natalia V. Veselnitskaya, in 2016 — an action that would have undercut the president’s claims to ignorance of the meeting. Mr. Cohen told investigators that he personally briefed members of the Trump family on the Moscow project “approximately 10” times during the campaign. And Mr. Gates told Mr. Mueller’s investigators that he remembered a campaign meeting in which the younger Mr. Trump mentioned the offer of Russian assistance against Mrs. Clinton.
On the other side of the Capitol, the Democrat-led House Intelligence Committee was trying to get its investigation off the ground, as members grappled with what actions — including possible impeachment — ought to follow the release of the special counsel’s report.
Democrats used their first hearing on the Russian interference detailed in Mr. Mueller’s 448-page report to publicize details of what the special counsel called Russia’s “multiple, systematic efforts to interfere in our election.”
Mr. Mueller concluded there was not enough evidence to charge anyone on the Trump campaign with conspiring with the Russians, but his investigation suggested that Mr. Trump was elected with the assistance of a foreign power and noted more than 100 meetings between his advisers and Russians.
“Of all the questions that Mueller helped resolve, he left many critical questions unanswered,” said Representative Adam B. Schiff of California, the committee’s chairman.
Mr. Schiff said that the committee, which oversees American intelligence agencies, had not been briefed on the status of a counterintelligence inquiry into whether Russia has compromised Mr. Trump or his associates, despite repeated requests. Mr. Schiff said later he was “running out of patience” and could soon issue a subpoena to force law enforcement officials to brief lawmakers.
Committee Republicans, dismissing Mr. Mueller’s report as a “shoddy political hit piece,” said the Russian threat had little to do with Mr. Trump and charged anew that biased officials within the F.B.I., State Department and other government agencies had conspired with Democrats to tarnish Mr. Trump’s candidacy and presidency.
“The entire scheme has now imploded and the collusion accusation has been exposed as a hoax,” said Representative Devin Nunes of California, the panel’s top Republican.
The contrast highlighted the Democrats’ dilemma as they searched for ways to engage the public with Mr. Mueller’s findings. The House Judiciary Committee held a similar hearing on Monday that focused on Mr. Mueller’s obstruction of justice investigation but lacked testimony from anyone involved in the case.
With the White House blocking key witnesses and government officials who may have aided Mr. Mueller’s investigators, Democrats were left to question three former government officials who could only speculate on the investigation.
“Understand that I have no access to supporting information or investigative detail other than what is provided in the special counsel’s report,” said Stephanie Douglas, a former high-level national security official at the F.B.I.
Ms. Douglas and Robert Anderson, a former F.B.I. official with experience in spying cases, said the report had clearly found troubling and potentially compromising behavior by the younger Mr. Trump; Paul Manafort, the former campaign chairman; Michael T. Flynn, a former national security adviser; and others.
“If you are a foreign power and you have a campaign or individuals who are willing to entertain receiving information that you are collecting for their benefit,” Ms. Douglas said, “I think that is a tacit approval of that action.”
Mr. Anderson said Mr. Mueller’s report showed “absolute classic tradecraft of Russia and Russian intelligence services.”