US President-elect Donald Trump along with his son Donald, Jr., arrive for a press conference at Trump Tower in New York, as Allen Weisselberg (C), chief financial officer of The Trump, looks on.

President Donald Trump on Thursday said he was surprised to learn that his eldest son, Donald Trump Jr., has been subpoenaed to testify before the Senate Intelligence Committee about his contacts with Russians during the 2016 presidential campaign.

"I was very surprised," Trump told reporters at the White House, noting that he had recently seen Republican Senate Intelligence Committee Chairman Richard Burr, R-N.C., say, "there was no collusion."

"My son is a very good person, works very hard," Trump continued. "The last thing he needs is Washington, D.C. I think he'd rather not ever be involved."

"He's now testified for 20 hours or something, a massive amount of time," Trump said. "The Mueller report came out, and that's the bible, and they said he did nothing wrong."

That's not what the Mueller report said, however. Trump's eldest son declined to speak voluntarily to Mueller and his team.

But the testimony Trump Jr. gave to various congressional committees about the 2016 meeting came under scrutiny after former Trump campaign aide Rick Gates gave a conflicting account under oath about what happened in the days leading up to the meeting.

Trump Jr. testified that he spoke about the meeting in advance to just two people: his brother-in-law, Jared Kushner, and Paul Manafort, Trump's then-campaign chairman.

But according to the published Mueller report, Gates testified that Donald Jr. told a much larger group of Trump family members and campaign staff at a regular morning meeting that "he had a lead on negative information about the Clinton Foundation." According to Gates, "Trump Jr. said the information was coming from a group in Kyrgyzstan and that he was introduced to the group by a friend."

On Thursday, the president defended the premise of the now infamous meeting. "The only thing is, it's oppo research," Trump said. "It was a nothing meeting," he added, before going on to describe what he claimed were suspicious circumstances under which the meeting was arranged.

"My son is a good person. My son testified for hours and hours. My son was totally exonerated by Mueller, who, frankly, does not like Donald Trump, me, this Donald Trump," the president continued.

"And frankly, for my son, after being exonerated to now get a subpoena, to go again and speak again, after close to 20 hours of telling everybody that would listen about a nothing meeting? Yeah, I'm pretty surprised. I'm just really surprised," he said.

Asked whether Trump Jr. should fight the subpoena, Trump avoided a yes or no answer. "Well, we'll see what happens," he said. "I'm just very surprised, I really am."

This is a developing story. Please check back for updates.