8:58 A.M.-11:47 A.M.

The New York Times contacts the White House and key agencies for answers.

With the help of other Times reporters who cover the administration, I ask members of Mr. Trump’s team questions that they have uniformly come to detest: What, exactly, did the president mean by the Twitter posts? And what immediate action will be taken, if any, to carry out his orders?

9:14 A.M.

Customs and Border Protection says to ask the White House.

A spokeswoman for Customs and Border Protection, the agency that patrols the border, informs us exactly where to go to get answers about Mr. Trump’s declaration that the caravan contains criminals and people from the Middle East: 1600 Pennsylvania Avenue.

I can’t speak to the President’s tweet. You might ask the WH where they got the info.

11:02 A.M.

The Department of Homeland Security has numbers, but not answers.

Asked whether Mr. Trump’s statement about the caravan comes from any intelligence the agency has seen, a spokeswoman for the Department of Homeland Security, speaking on the condition of anonymity because she lacks authorization to comment on the record — provides general statistics about bad actors that Customs and Border Protection apprehended this year or prevented from entering the country last year. None of the countries mentioned are in the Middle East.

On background, in FY 18, CBP apprehended 17,256 criminals, 1,019 gang members, and 3,028 special interest aliens from countries such as Bangladesh, Pakistan, Nigeria, and Somalia. Additionally, C.B.P. prevented 10 known or suspected terrorists from traveling to or entering the United States every day in fiscal year 2017.

1:41 P.M.

The State Department would like these questions asked elsewhere.

A spokeswoman for the State Department, speaking — once again — on the condition of anonymity, sends a long list of talking points about the caravan, saying that the administration is “closely following” the group, is concerned about it and is working closely with Central American and Mexican officials to discourage people from making “this dangerous journey.”

But the spokeswoman will not answer questions about whether Mike Pompeo, the secretary of state, or anyone at the department has begun the process of cutting off aid, or when that will happen. She will not touch the president’s statement about criminals and Middle Easterners in the caravan.

The President has made clear that countries receiving assistance from the United States should support our interests. We refer you to the White House for additional information.

2:45 P.M.

Trump speaks to reporters, shedding no light.

The president, on his way to a campaign stop in Texas, speaks to reporters outside the White House, restating his warnings and complaints about the caravan but offering no new information. When Jon Karl of ABC News asks what evidence Mr. Trump has that the caravan is filled with criminals and people from the Middle East, the president becomes testy.

“You know what you should do, Jon? Go into the middle of the caravan, take your cameras, and search. Okay? Search. No, no. Take your — Jon, take your camera, go into the middle, and search. You’re going to find MS-13, you’re going to find Middle Eastern, you’re going to find everything. And guess what? We’re not allowing them in our country. We want safety.”

4:02 P.M.

Asked and answered, the White House says.

A White House spokesman responds to a second request for answers about the president’s tweets by referring back to the comments he has made earlier, in which he did not answer any of the questions I have posed.

He just gaggled on this topic. Do you still need info?

(Yes, I do.)

4:47 P.M.

Homeland security sends a list of enforcement actions against “special interest aliens” in 2018.

The spokeswoman sends a follow-up email listing the countries of origin — some in the Middle East — for “special interest aliens” that Customs and Border Protection has taken enforcement actions against in 2018. She provides no additional information about how or whether they are tied to the caravan.

5:28 P.M.

The White House says there is evidence, but supplies none.

Sarah Huckabee Sanders, the president’s press secretary, tells reporters in the White House driveway that the president “absolutely” has evidence that there are Middle Easterners in the caravan. She cites a statistic that the Department of Homeland Security sent earlier about the 10 known or suspected terrorists who try to enter the country illegally each day.

4:20 P.M. Tuesday

Mr. Trump acknowledges he has no proof.

Mr. Trump, questioned by reporters in the Oval Office about his assertions about the caravan, says, “There's no proof of anything, but there very well could be” Middle Easterners who have joined the group. Minutes later, Tyler Q. Houlton, the spokesman for the Department of Homeland Security, tweeted, “Citizens of countries outside Central America, including countries in the Middle East, Africa, South Asia, and elsewhere are currently traveling through Mexico toward the U.S.”

Ron Nixon contributed reporting.