President Donald Trump said Wednesday that he may have previously heard about his son and top campaign staff meeting with a Russian lawyer in June 2016, a stunning contradiction of his earlier statements on the matter.

Emails released Tuesday by Donald Trump Jr., ahead of a New York Times story on the same messages, show the President’s son responding enthusiastically to the promise of dirt on Hillary Clinton provided as part of a Russian government effort to aide his father’s campaign.

On Wednesday afternoon, Trump told Reuters that “No. That I didn’t know. Until a couple of days ago, when I heard about this. No I didn’t know about that,” referring to the meeting between Russian lawyer Natalia Veselnitskaya and Donald Trump Jr., Jared Kushner and Paul Manafort.

Trump changed his tune later in the day, when he told reporters on Air Force One: “In fact maybe it was mentioned at some point,” referring to the meeting. (Reporters on the plane initially thought the conversation was off-the-record, but the President said otherwise on Thursday.)

Asked whether he had been told the meeting was about Hillary Clinton and dirt against her, Trump said no, according to a White House pool report. On Thursday, Trump called the meeting “very standard.”

Senators on both sides of the aisle, after the emails were published, expressed interest in having Trump Jr. testify about the meeting. And multiple complaints have accused the campaign of illegally accepting a contribution — in the form of the promised damaging information on Clinton — from a foreign national.

Vice President Mike Pence said Tuesday he was unaware of the meeting.

Trump also mentioned seeing, according to the White House pool, “something about her being in congress recently talking to members,” possibly a reference to a report in The Hill that Veselnitskaya attended a House Foreign Affairs Committee meeting, and a dinner at which Rep. Dana Rohrabacher (R-CA) was in attendance, days before meeting with the campaign at Trump Tower.

“She had meetings with various people,” Trump said. “So it’s the same thing.

This post has been updated.