President Trump will be ordering the construction of his signature Mexican border wall on Wednesday, according to a report.

White House officials told the New York Times that Trump is expected to sign the executive order — directing that federal funds be focused on creating the structure — during an appearance at the Department of Homeland Security.

Building a wall on the border of Mexico was one of Trump’s biggest promises during his campaign. He ultimately believes that doing so would put a stop to the influx of illegal immigrants coming into the United States today.

“Big day planned on NATIONAL SECURITY tomorrow. Among many other things, we will build the wall!” Trump tweeted on Tuesday night.

While the wall won’t be completed for quite some time, officials told the Times that the president is also considering a policy that would temporarily stop refugees from coming from Syria, as well as other majority-Muslim nations that are deemed “terror-prone.”