Good evening. There's breaking news out of the Pentagon, or maybe it's out of Iraq, or possibly the White House.

At this point, we're not exactly sure, and that's kind of the point.

Someone late this afternoon sent out an official letter, notifying the Iraqi government that U.S. troops there would begin repositioning,

and what would appear to be the first step in leaving the country outright.

Then a few hours later, Secretary of Defense, Mark Esper, said that the letter was sent in error, actually saying his staff was,

quote, trying to figure out, unquote, what the memo is, which left everyone trying to figure out just what's going on.

And the frightening answer is about the letter and just about everything other thing that's happened since the U.S. killed the Iranian general.

We simply do not know. That's where the last three days that the United States and Iran trading threats and mobilizing forces suggest we are.

That's where the last three days, developments and seemingly unanticipated consequences, suggest we are.

In Iran, there have been giant crowds publicly mourning the man who was responsible for the deaths of hundreds of American troops in Iraq,

and many other civilians in Iraq and Syria and elsewhere.

The Iranians announced they're pulling out of the international agreement, limiting their nuclear program.

The Iraqi parliament voted to expel U.S. forces.

In addition, the president on Saturday threatened to target Iranian cultural sites in retaliation for any future attacks,

which his secretary of state on Sunday tried to deny, which the president then reiterated, which his secretary of defense today denied.

We'll talk about all that shortly with CNN's Jim Acosta, the White House and Democratic presidential candidate Bernie Sanders.

But first, CNN's Barbara Star has been working her sources of the Pentagon.

Barbara, what's the latest on this letter regarding troop movements?

Well, this is a letter that apparently got leaked by the Iraqis to some members of the news media, filtering its way.

Across the media. And what the Pentagon said today is once they checked into it that the letter was poorly written, was a mistake, was never supposed to come out.

What it says is that U.S. troops are repositioning in Iraq, and that is true.

But it also goes on to talk about future onward movement of U.S. troops, very strongly suggesting that U.S. troops are leaving Iraq.

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