(CNN) White House senior adviser Stephen Miller indicated on Monday that President Donald Trump has not quite made the decision to shut down the border, saying it depends on how the week goes, according to notes from a conference call taken by a listener and obtained by CNN.

"We will see how much progress we are able to make in the ensuing days, in terms of getting more enforcement with Central and South America, so that we are not getting swamped by meritless asylum claims predominantly from Central America," Miller told top administration immigration surrogates on a conference call, according to the notes.

Trump repeated his threat on Friday to close the border between the US and Mexico, and said he would act this week if Mexico didn't step up.

"If Mexico doesn't immediately stop ALL illegal immigration coming into the United States throug (sic) our Southern Border, I will be CLOSING the Border, or large sections of the Border, next week," he tweeted.

Miller's comments on the call signal that White House officials hope their threats will motivate Central American countries to take action and step up enforcement.

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