A bomb has dropped on the Trump Russia story.

Russian ambassador told Moscow that Kushner wanted secret communications channel with Kremlin https://t.co/pb9txA858U — Washington Post (@washingtonpost) May 26, 2017

CHRIS HAYES: We once again have breaking news tonight about the Trump campaign and Russia, and it is a doozy. "The Washington Post" citing US Officials briefed on intelligence reports reporting that Jared Kushner and Russia's ambassador to Washington, Sergey Kislyak, discussed the possibility of setting up a secret and secure communications channel between Trump's transition team and the Kremlin using Russian diplomatic facilities in an apparent move to shield their pre-inauguration monitoring. According to the post, Ambassador Kislyak said Kushner suggested using Russian diplomatic facilities in the United States for the communications, and reportedly Kislyak was taken aback by the suggestion of allowing an American to use Russian communications gear at its embassy or consulate. A proposal that would have carried security risks for Moscow as well as the Trump team.

So it appears that Jared Kushner met with the Russian ambassador in secret, reportedly to set up a back channel possibly in Russian diplomatic facilities. Kushner then omitted this meeting on his SF-86 security clearance form. And when he was called on it months later in April of this year, his lawyers called it an error. But if Kislyak's account is accurate, how likely is it that Jared Kushner just forgot about a cloak and dagger meeting with a foreign agent to set up a secret back channel? How likely is it that his omission of that meeting to US Officials was simply an oversight? Jared Kushner could have read on the clearance form he filled out, that knowingly falsifying or concealing information is a felony punishable by up to five years in prison. Joining me now by phone is one of the authors of that report, "Washington Post" reporter Greg Miller. Greg, put some context for this. How unusual is this?

GREG MILLER, WASHINGTON POST: It's hard to even assess how unusual it is. I mean I just can't think of any scenario in which an incoming administration, a senior adviser and, in fact, a relative of an incoming president would want to -- would suggest this sort of secret back channel communication with Moscow, let alone doing so using Russian communications facilities.

HAYES: What is the context of this meeting?

MILLER: Well, so it comes in early December, so about a month after the election. So this is before, you know, the Flynn meetings that -- Flynn conversations got the national security adviser ultimately pushed out of office. And it's at a time when both sides, Russia, and the Trump transition team, are sort of still, you know, preparing for a warming of relationships.

HAYES: And does this meeting happen in Trump Tower in New York?

MILLER: Yes. The meeting happened in Trump Tower on December 1st or 2nd. The White House hasn't been clear on the specific date. And we've known about that meeting for quite a while. We've known that Kushner and Flynn met with Kislyak there and then. We didn't know until tonight that they had discussed in that meeting setting up a secure, secret, separate channel for communications coming out of that session.

HAYES: And we know that your reporting suggests based on intelligence intercepts of a report on the conversation that Kislyak sent to other Russian officials, is that correct?

MILLER: That's right.

HAYES: That's an important point here. So this is Kislyak reporting back to Moscow.

MILLER: This is not the US monitoring this meeting at Trump Tower, eavesdropping on US Officials in the US. This is Kislyak calling Moscow or communicating with Moscow about what happens during this meeting. Of course, we know pretty well now that Kislyak and his communications are under heavy surveillance by the United States.

HAYES: We also know -- I mean just a detail that strikes me as important about this meeting, that was a period of time in which lots of people were coming to Trump tower and generally coming in the front, and there was a kind of almost like C-Span camera in that front lobby where you could basically see the comings and goings. This clearly happened in a way in which Kislyak entered the building without being caught on camera, correct?

MILLER: Yeah. We've spent a lot of reporting energy trying to locate evidence of this visit, and you're right. So Kislyak didn't go through the same front door that so many other people did to meet with this Trump team.

HAYES: So what is the response from the white house or from the Kushner attorneys?

MILLER: So a very limited response from the white house on this one. You see in our story there is no comment from the White House. I can only tell you that there was significant back and forth from the White House. We gave them every opportunity to provide an explanation for what happened here, and they declined to do so on the record.

HAYES: One really interesting detail in your story is that the story says that this information was first brought to your reporter's attention by an anonymous letter, is that correct?

MILLER: Yes, that's right. So quite some time ago, we got this letter in the mail. My colleague Ellen Nakashima got it. It came in her mailbox. It was typed. It had no signature. It gave no means of tracing this back to the source, but it had a lot of information in it about things that had been happening in Trump Tower. And it appeared to be from somebody inside the transition or inside Trump Tower who was concerned about what this person was seeing.

HAYES: And a lot of what's written or conveyed in this letter has sort of come -- become true over time. It's taken a while for a lot of this stuff to surface, including this detail about this discussion over a back channel or a private channel of communications with Moscow.

Again I just want to -- I'm trying to sort of bend over to read this as charitably as possible. So I mean is it possible that they were setting up lots of different back channels with lots of different foreign leaders?

MILLER: Well, we don't -- I mean I suppose it's possible. Clearly, they were in communication and meeting with a lot of leaders, a lot of foreign leaders. Most of them, as you point out, were coming through the front door, not the back behavior here is part of what's interesting and newsworthy, I think, right? The way this was all handled. The context here, of course, is that these are meetings with Russian officials just weeks after an election that Russia had spent months in an unprecedented sort of campaign, attempting to upend or interfere with.

HAYES: So I mean it's really -- I mean on the one hand, you can argue sometimes that it's appropriate for incoming administrations to have contact with foreign governments and so forth.

MILLER: Certainly.

HAYES: But this was extraordinary.

MILLER: Yeah.

HAYES: Greg Miller, remarkable reporting. Thank you for your time tonight. ...

And bombshells on a Friday of a long weekend is the new normal.