WASHINGTON (AP) — President Donald Trump is signing two executive orders in keeping with campaign promises to boost border security and crack down on immigrants living in the U.S. illegally.

The president signed the two orders Wednesday during a ceremony at the Department of Homeland Security after honoring the department’s newly confirmed secretary, retired Gen. John Kelly.

The executive orders jumpstart construction of a U.S.-Mexico border wall, one of his signature campaign promises, and strip funding for so-called sanctuary cities, which don’t arrest or detain immigrants living in the U.S. illegally.

Trump says he expects construction of the border wall to begin within months. U.S. taxpayers are expected to pay for the upfront costs, though Trump continues to insist that Mexico will somehow reimburse the United States.

Trump tells ABC News, “There will be a payment,” but it may be in a “complicated form.”