Senior White House officials sent a clear message Sunday: President Donald Trump is serious. It would take “something dramatic” over the next few days to convince Trump not to go through with his threat to close the southern border with Mexico, acting White House chief of staff Mick Mulvaney said. “Why are we talking about closing the border? Because not for spite and not to—not to try and—and—and undo what’s happening but to simply say look, we need the people from the ports of entry to go out and patrol in the desert where we don’t have any wall,” he said on ABC’s This Week.

NEW: Acting White House chief of staff Mick Mulvaney tells @jonkarl it would take "something dramatic" for President Trump not to close the U.S.-Mexico border https://t.co/GtOTcEQrgO #ThisWeek pic.twitter.com/VR9ICtDKci — This Week (@ThisWeekABC) March 31, 2019

White House counselor Kellyanne Conway also warned that the threat could become a reality. “It certainly isn’t a bluff,” Conway told Fox News Sunday. “You can take the president seriously.” Conway and Mulvaney both spoke two days after Trump said there was “a very good likelihood” he would close the border unless Mexico did “something.”

Mulvaney and Conway also defended the move to cut off aid to Guatemala, Honduras, and El Salvador, saying the three countries need to do more to prevent migrants moving north. Even though some have said that cutting off the aid would only push more migration, the senior White House officials pushed back against that idea. “The conditions are already awful,” Conway said. “The executive branch has done so much to try to mitigate these awful circumstances, and we need to send a message back to these countries, too.” Mulvaney also dismissed concerns. “If we’re going to give these countries hundreds of millions of dollars, we would like them to do more,” he said on CNN’s State of the Union. “If it’s working so well why are the people still coming?”

Mick Mulvaney on the Trump administration proposing aid cuts to several Central American countries: “If it's working so well, why are the people still coming? Why are these historic numbers? Again, 100,000 people will cross the border this month alone. That is a crisis” #CNNSOTU pic.twitter.com/pgVdBI8hX6 — State of the Union (@CNNSotu) March 31, 2019

Even as the two administration officials wanted to make clear that the plan to close the border could soon become a reality, some unnamed officials are raising concerns about whether the plan is even doable. Axios reports that administration officials say they aren’t even close to being prepared to carry out this type of plan on such a short timeline. “The widespread view within the White House and at the Department of Homeland Security is that it’s a terrible and unworkable idea,” reports Axios. But still, the issue is being analyzed since Trump has mentioned it numerous times.

Some Democrats are also skeptical the plan is workable. “When the president says he’s going to close the border, that is a totally unrealistic boast on his part,” Sen. Dick Durbin said on NBC’s Meet the Press. “What we need to do is focus on what’s happening in Central America, where three countries are dissembling before our eyes, and people are desperately coming to the United States.”