United States officials announced on Thursday that they had awarded contracts to four companies to build prototypes for a wall along the Mexico border, BBC reported. This is the first major step the country has taken towards building the structure, one of President Donald Trump’s major campaign promises.

US Customs and Border Protection officials said that the contracts were awarded to Caddell Construction in Alabama, Fisher Industries in Arizona, Texas Sterling Construction and WG Yates and Sons Construction in Mississippi. Each contract is worth $500,000 (approximately Rs 3.2 crore).

The concrete prototypes, to be built over the next few months, will be 30 ft high. Once constructed, officials will evaluate them by installing them at the border in San Diego, The New York Times reported.

The prototypes will help refine the design standards of the eventual border wall. “Testing will look at things like the aesthetics of it, how penetrable they are, how resistant they are to tampering and scaling or anti-climb features,” said Acting Customs and Border Protection Deputy Commissioner Ronald Vitiello.