Trump has come out in support of his son-in-law Jared Kushner, following reports the aide tried to set up a secret communication line with Moscow.
In a statement given to the New York Times, Mr Trump praised the “great job” Mr Kushner is doing.
But he did not directly address allegations made against the man married to his eldest daughter, Ivanka.
It has been claimed Mr Kushner discussed setting up a backchannel with the Russian ambassador in December.
The New York Times and Washington Post said he wanted to use Russian facilities to avoid U.S. interception of discussions with Moscow.
He is reported to have done so before Mr Trump assumed the presidency, so would have been a private citizen at the time.
The allegations came after Mr Kushner was said to be under scrutiny as part of the FBI inquiry into alleged Russian meddling in the 2016 election.
Reports in the U.S. say investigators believe he has relevant information, but is not necessarily suspected of a crime.
Mr Trump – who is said to have met with attorneys at the White House on Sunday – did not falter in his support for Mr Kushner, who has taken a role as a senior White House aide.
“Jared is doing a great job for the country. I have total confidence in him,” he said in the statement to the New York Times.
“He is respected by virtually everyone and is working on programs that will save our country billions of dollars. In addition to that, and perhaps more importantly, he is a very good person.”
Mr Trump’s comments came after senior administration officials had moved to play down the allegations, without addressing whether or not they were true.
Homeland Security Secretary John Kelly told ABC News on Sunday it was “normal” and “acceptable” to establish back channels with foreign powers.
“Any way that you can communicate with people, particularly organisations that are maybe not particularly friendly to us, is a good thing and, again, it comes back to whatever the communication is, comes back into the government and shared across the government.”
Meanwhile, Mr Trump’s National Security Advisor HR McMaster said, generally speaking, “we have back-channel communication with a number of countries”.
Mr Trump had earlier taken to Twitter to vent his frustrations with the “fake news media”.
“It is my opinion that many of the leaks coming out of the White House are fabricated lies made up by the #FakeNews media,” he wrote.
“Whenever you see the words ‘sources say’ in the fake news media, and they don’t mention names it is very possible that those sources don’t exist but are made up by fake news writers. #FakeNews is the enemy!”