Jared Kushner, President Trump’s senior adviser and son-in-law, spent two hours Monday answering questions from Senate investigators about his contacts with Russian officials, as the various probes into Russian interference during the 2016 campaign entered a new phase involving some of those closest to Trump.

After his closed-door questioning, Kushner spoke briefly to reporters outside the White House.

“Let me be very clear: I did not collude with Russia, nor do I know of anyone else in the campaign who did so,” he said. “I had no improper contacts. I have not relied on Russian funds for my businesses, and I have been fully transparent in providing all requested information.

“Since the first questions were raised in March, I have been consistent in saying I was eager to share whatever information I have with investigating bodies, and I have done so today,’’ he said. “All of my actions were proper.’’

Legal experts expect that all of Kushner’s answers to the Senate Intelligence Committee will be shared with special counsel Robert S. Mueller III, who is conducting a separate investigation of potential criminal activity surrounding Russian meddling and key figures in the Trump campaign.

White House senior adviser Jared Kushner, center, accompanied by his attorney, Abbe Lowell, right, arrives on Capitol Hill on July 24. (Oliver Contreras for The Washington Post)

Trump spokeswoman Sarah Huckabee Sanders said the president “was very proud of Jared for voluntarily going to the Hill and being very transparent with every interaction that he’s had. He thought Jared did a great job and was very glad that he was able to go through that process and lay everything out and I think show the members of that committee as well as everybody else what a witch hunt and hoax this whole thing is.’’

Kushner dismissed outright the notion that Russia could be responsible for his father-in-law’s election victory. “Donald Trump had a better message and ran a smarter campaign, and that is why he won. Suggesting otherwise ridicules those who voted for him,’’ he said.

Kushner’s appearance Monday will be followed by further questioning Tuesday — again, behind closed doors — before the House Intelligence Committee, which is also probing Russian election-year meddling.

U.S. intelligence agencies have concluded that the Russian government orchestrated a far-reaching campaign to disrupt last year’s presidential campaign and influence the outcome in Trump’s favor. A major question for the current investigations is whether any Trump associates acted to help or advise the Russian effort.

Kushner and the White House used the grilling to offer their most detailed refutation — in the form of an 11-page written statement — of the idea that anyone in the campaign sought to coordinate with people acting on behalf of the Russian government.

“Hopefully, this puts these matters to rest,’’ Kushner wrote.

Kushner’s statement detailed four meetings he had with Russian officials or nationals during the 2016 campaign and transition period. He described them as brief and unremarkable contacts in his role as the Trump campaign’s liaison to foreign governments.

(Jenny Starrs/The Washington Post)

[Read Kushner’s prepared statement]

Kushner wrote that his first meeting with a Russian official was in April 2016 at the Mayflower Hotel in Washington, where Trump delivered a major foreign policy speech, the execution of which Kushner said he oversaw. Kushner wrote that he attended a reception to thank the event’s host, Dimitri Simes, publisher of the National Interest, a foreign policy magazine. Simes introduced Kushner to four ambassadors at the reception, including Russian Ambassador Sergey Kislyak, Kushner said.

“With all the ambassadors, including Mr. Kislyak, we shook hands, exchanged brief pleasantries and I thanked them for attending the event and said I hoped they would like candidate Trump’s speech and his ideas for a fresh approach to America’s foreign policy,” he wrote. “The ambassadors also expressed interest in creating a positive relationship should we win the election. Each exchange lasted less than a minute; some gave me their business cards and invited me to lunch at their embassies. I never took them up on any of these invitations and that was the extent of the interactions.”

Kushner did not name the other three ambassadors he met at the reception, and he denied having had any other contact with Kislyak during the campaign, disputing a report by Reuters that he had two phone calls with the ambassador.

“While I participated in thousands of calls during this period, I do not recall any such calls with the Russian Ambassador,” Kushner wrote. “We have reviewed the phone records available to us and have not been able to identify any calls to any number we know to be associated with Ambassador Kislyak and I am highly skeptical these calls took place.”

In fact, he said that on Nov. 9, the day after the election, when the campaign received a congratulatory note from Russian President Vladimir Putin, Kushner tried to verify it was real and could not remember Kislyak’s name. “So I sent an email asking Mr. Simes, ‘What is the name of the Russian ambassador?’ ” Kushner wrote.

Kushner also described attending a June 2016 meeting organized by his brother-in-law Donald Trump Jr. with a Russian attorney. He said it was listed on his calendar as “Meeting: Don Jr. | Jared Kushner.” He wrote that he arrived at the meeting late, and that when he got there the Russian lawyer was talking about a ban on adoption of Russian children by Americans.

“I had no idea why that topic was being raised and quickly determined that my time was not well-spent at this meeting,” Kushner wrote. “Reviewing emails recently confirmed my memory that the meeting was a waste of our time and that, in looking for a polite way to leave and get back to my work, I actually emailed an assistant from the meeting after I had been there for 10 or so minutes and wrote, ‘Can u pls call me on my cell? Need excuse to get out of meeting.’ ”

Kushner also detailed two interactions with Russian officials during the transition period, before Trump was sworn in as president on Jan. 20. The first, on Dec. 1, was a meeting with Kislyak at Trump Tower in New York. Retired Lt. Gen. Michael T. Flynn, who would become the president’s national security adviser, also attended.

“I stated our desire for a fresh start in relations,” Kushner wrote. “Also, as I had done in other meetings with foreign officials, I asked Ambassador Kislyak if he would identify the best person (whether the Ambassador or someone else) with whom to have direct discussions and who had contact with his President. The fact that I was asking about ways to start a dialogue after Election Day should of course be viewed as strong evidence that I was not aware of one that existed before Election Day.”

Kushner wrote that Kislyak addressed U.S. policy in Syria and wanted to “convey information from what he called his ‘generals.’ ” But Kislyak said they could not come to the United States and “asked if there was a secure line in the transition office to conduct a conversation.”

Kushner said that he or Flynn explained there were no such lines, and that Kushner asked Kislyak if the Russians had “an existing communications channel at his embassy we could use where they would be comfortable transmitting the information they wanted to relay to General Flynn.” He wrote that Kislyak said “that would not be possible,” and they agreed to wait until after the inauguration to receive the information.

The Washington Post first reported in May on Kushner and Kislyak’s discussions about establishing a secret means of communication, although Kushner suggested in his testimony that the channel would have been for the purpose of this one meeting.

“I did not suggest a ‘secret back channel,’ ” he wrote. “I did not suggest an ongoing secret form of communication for then or for when the administration took office. I did not raise the possibility of using the embassy or any other Russian facility for any purpose other than this one possible conversation in the transition period.”

The second transition-period meeting Kushner said he had with Russians was on Dec. 13, when, at the urging of Kislyak, he met with Sergey Gorkov, a banker with “a direct line” to Putin.

On Dec. 6, the Russian Embassy asked Kushner to meet with Kislyak on Dec. 7, and Kushner declined, he wrote. The Russians asked if he could meet on Dec. 6, and Kushner declined again, he wrote. Kislyak then requested a meeting with Kushner’s assistant — “and, to avoid offending the Ambassador, I agreed,” Kushner wrote.

Kislyak and Kushner’s assistant, whom Kushner did not name, met on Dec. 12, and Kislyak requested that Kushner meet with Gorkov, “who could give insight into how Putin was viewing the new administration and best ways to work together.”

Kushner agreed to meet Gor­kov, making room in his schedule for him the next day. Their meeting lasted 20 to 25 minutes, Kushner wrote, and Gorkov presented two gifts — “a piece of art from Nvogorod, the village where my grandparents were from in Belarus,” and a bag of dirt from there. Kushner gave the gifts to his assistant and asked him to formally register them with the transition office.

During the meeting, Kushner wrote, Gorkov told him about his bank and discussed the Russian economy, expressing “disappointment with U.S.-Russia relations under President Obama and hopes for a better relationship in the future.” Kushner wrote that “no specific policies were discussed,” including sanctions imposed by the Obama administration.

Ashley Parker contributed to this report.