It is the first criminal charge in the FBI probe into collusion with Moscow.

The meeting, on March 31, 2016, has taken on new importance after prosecutors said publicly that Papadopoulos had pleaded guilty to making false statements about the nature of his contacts with Russians last year.

He has agreed to cooperate with investigators working for special counsel Robert Mueller.

Court documents filed by Mueller show that Papadopoulos said at the meeting of foreign policy advisers "that he had connections that could help arrange a meeting between then-candidate Trump and President Vladimir Putin."

"I don't remember much about that meeting. It was a very unimportant meeting," Trump said.

A photograph on Trump's Instagram and Twitter accounts shows Papadopoulos sitting at the same table with Trump, future Attorney General Jeff Sessions and several others.

His plea was made public this week.

Federal investigators this week charged Trump's former campaign manager Paul Manafort and another ex-aide, Rick Gates, with money laundering and other crimes. In a court filing on Friday, Mueller estimated he would need three weeks to present his case against Manafort and Gates if it went to trial.

Both pleaded not guilty.

More Senate sessions for Sessions

Trump denies any collusion with Russia, and Moscow denies interfering in the 2016 election. Trump has said he thinks the Department of Justice — overseen by Sessions — should look into his former presidential rival, Hillary Clinton, and her campaign during the presidential primary race.

"The saddest thing is, because I am the president of the United States, I am not supposed to be involved with the Justice Department. I'm not supposed to be involved with the FBI. I'm not supposed to be doing the kind of things I would love to be doing. And I am very frustrated by that," he said.

On the other side, Sessions is under pressure from Senate Democrats to testify again about the Trump campaign's Russia contacts.

In testimony to the Senate Judiciary Committee, Sessions has denied knowing anything about contacts between the campaign and Russians or Russian government intermediaries.

Senate Democrats, including Al Franken of Minnesota, Patrick Leahy of Vermont and Richard Blumenthal of Connecticut, have accused Sessions of lying under oath. Leahy said Sessions' prior accounts are "impossible to reconcile" with court papers unsealed this week.

Corker gives it to Trump again

"President Trump's pressuring of the Justice Department and FBI to pursue cases against his adversaries and calling for punishment before trials take place are totally inappropriate and not only undermine our justice system but erode the American people's confidence in our institutions," Republican Senator Bob Corker, who has frequently sparred with Trump, said in a statement.

jbh/bw (Reuters, AP)