President Donald Trump on Sunday took a vague tack to explaining how exactly he plans to get Mexico to pay for his proposed wall along the United States’ southern border.

On the campaign trail, Trump often pledged to crowds at his rallies that he would “build a great great wall” and “have Mexico pay for that wall.”

On Sunday, however, Trump tweeted that Mexico would pay “eventually,” “at a later date” and “in some form” for his proposed wall. He did not specify a specific date or schedule for that payment, and did not say what kind of remuneration it would entail.

Eventually, but at a later date so we can get started early, Mexico will be paying, in some form, for the badly needed border wall. — Donald J. Trump (@realDonaldTrump) April 23, 2017

In March, the White House requested more than $1 billion from Congress to begin construction.

Attorney General Jeff Sessions on Sunday nevertheless insisted that Trump will get the wall “paid for one way or the other.”

“There are a lot of ways we can find money to help pay for this,” Sessions said. “There’s no doubt about that.”