President Donald Trump’s budget director Mick Mulvaney reassured supporters that the White House would build a wall, previewing it to reporters at the White House press briefing.

“We are absolutely dead serious about the wall,” Mulvaney said, calling it one of the president’s “top three” budget priorities.

He pushed back against reports that said the administration was reducing funding for the border wall, pointing out that Trump’s budget was a dramatic increase in border security from the previous year.

The 2017 budget included $1.5 billion for border security and $3 billion for the Department of Homeland Security. The 2018 budget, he explained, requested $2.6 billion and $4.5 billion for DHS.

The text of the budget specifies funds for “a physical wall” on the southern border of the United States.

The funding would help fund replacement wall, new wall, roads and infrastructure for the wall as well as land acquisition.

The director suggested that supporters should be patient regarding the wall, noting that it was only the first step in the lengthy project.

“Keep in mind, you can’t just … you don’t automatically magically build a wall in the middle of nowhere,” he said.

On Monday, Mulvaney previewed a $1.6 billion request for “actual bricks-and-mortar construction.”

He described “competition” process for getting the best possible wall design for each area of the Southern border, citing 4-8 prototypes that were currently being constructed.

“We fully expect that different barriers will serve best in different areas,” Mulvaney said.