The Pentagon has authorized 1 billion dollars for bolstering security on the United States’ border with Mexico, Acting Defence Secretary Patrick Shanahan said on Monday.

The funding will go towards constructing fencing almost 92 kilometres in length and 5.5 metres in height near El Paso in the state of Texas, as well as building roads and installing lighting.

A statement posted on the Pentagon‘s website said the move was “in support of the February 15 national emergency declaration on the southern border of the United States.” The goal is to prevent drugs from being smuggled over the border.

The infrastructure was described as “fencing,” not a “wall.” Building a wall along the US-Mexico border was a key campaign promise for Republican President Donald Trump in the 2016 election. The opposition Democrats have vehemently opposed efforts to build a wall.

After weeks of bickering, Republicans and Democrats agreed to a compromise during budget talks in February that saw Trump allocated 5.7 billion dollars for building a wall – much less than he had hoped for.

In response, Trump declared a national emergency last month, clearing the way for the president to take money from the Pentagon‘s construction budget and drug forfeitures and use it for wall construction.

Trump overruled a move by Congress to block the declaration of a national emergency on March 15, using the first veto of his presidency.

Democrats are hoping to block the veto in a vote on Tuesday, but they are not expected to muster the two-thirds majority required to do so. Even if they are successful, they would require that same majority in a second vote in the Republican-controlled Senate.