What we know - and don't know - about Jared Kushner's Russia contacts

— -- The revelation that Jared Kushner, the president's son-in-law and senior adviser, is a focus of the FBI for his contacts with Russia has prompted questions and concerns.

Kushner is being scrutinized in the agency's investigation into Russian meddling in the U.S. election over his meetings with at least two Russian officials, Moscow's ambassador to the U.S. and a banking executive, sources have told ABC News.

Here's what we know -- and don't know:

What do we know about the alleged back channel Kushner wanted to establish?

Two sources familiar with the matter told ABC News that Kushner did talk about establishing a back channel with the Russian ambassador last December. That conversation was first reported by The Washington Post and The New York Times.

The sources stress the conversation with the president's son-in-law was focused on the U.S. response to the crisis in Syria and other policy -related matters.

The meeting took place at Trump Tower in New York and included the Russian ambassador, Kushner and Michael Flynn, who went on to be Trump's first national security adviser.

What was the second meeting that Kushner was involved in?

The second meeting between Kushner and Kislyak took place in December, but it wasn't the only time that Kushner met with a powerful Russian during the transition.

Separately, the White House confirmed that also in December, Kushner met with Sergey Gorkov of Russian bank Vnesheconombank, or VEB, at the suggestion of Kislyak.

The subject of that conversation has not been publicly released.

A senior White House official said that the conversation was "general and inconsequential" and that Kushner took the meeting as part of his campaign role of interfacing with foreign dignitaries. But the bank described the discussion to ABC News as a "negotiation" in which "the parties discussed the business practices applied by foreign development banks, as well as most promising business lines and sectors."

The December meeting came as Kushner Companies, the family's real estate firm, is in the midst of what it has described in public statements as "active, advanced negotiations ... with a number of potential investors" about the redevelopment of the skyscraper it owns at 666 Fifth Avenue in New York City.

To date, neither Kushner nor the family real estate firm has explained the nature of the meeting with VEB. An official representing the Kushner firm responded to ABC News' questions on March 29, 2017, saying Kushner was the only executive from his family's real estate firm to attend.

"VEB is not providing financing, lending or any other services to Kushner Companies," the official said.

What does the White House say?

Kellyanne Conway, counselor to the president, reiterated during an interview this morning that "the president has expressed full confidence in Jared Kushner."

"The facts are that Jared Kushner has said from the very beginning he is willing to go and share any information that he has with Congress, with the FBI," she said on "Fox & Friends." "And as you heard Gen. [H.R.] McMaster, as you heard Secretary [of Homeland Security John] Kelly over this weekend say they are not concerned. Back channels like this are the regular course of business. And that's really all that we know."

She was asked to comment on Kushner's meeting with Gorkov, but said, "I cannot comment on any of that because there is no reason to, frankly."

At this afternoon's press briefing, press secretary Sean Spicer pointed to the "ongoing investigation" and read an earlier statement from Kushner's lawyers wherein he volunteered to meet with investigatory bodies to answer questions.

The president today retweeted a Fox News story with no byline citing one unnamed source that said the Russians were the first to suggest the idea of a back channel, not Kushner.

How is Washington reacting?

The Democratic National Committee called for Kushner's security clearance to be suspended until after the FBI investigation is concluded.

Sen. John McCain, R-Arizona, has been one of the Republicans most willing to criticize the administration, and the latest revelations have proved of concern for him.

During an interview in Australia over the weekend, said that he doesn't "like" reports of Kushner's meetings with Russian officials during the transition.

"I know that some administration officials are saying, 'Well, that's standard procedure,'" he said. "I don't think it is standard procedure prior to the inauguration of a president of the United States by someone who is not in an appointed position. And I think that [former FBI Director James] Comey, we now know, took action that he did in regards to then-candidate [Hillary] Clinton because of some false news that was being put out by the Russians. I mean, this becomes more and more and more bizarre. In fact, you can't make it up."

What questions remain?

As of now, Kushner's position with the White House appears to remain the same and his security clearance seems to have remained unchanged.

The content of the meetings -- both with Kislyak and Gorkov -- remains unknown, as does the motivation behind the second meeting, and why Kislyak allegedly urged Kushner to meet with Gorkov, per sources.