President Donald Trump’s “wall” along the U.S.-Mexico border would cost as much as $21.6 billion, and take more than three years to construct, Reuters has reported.

The agency based its report on a U.S. Department of Homeland Security internal report.

The report’s estimated price-tag is much higher than a $12-billion figure cited by Trump in his campaign and estimates as high as $15 billion from Republican House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell.

The report is expected to be presented to Department of Homeland Security (DHS) Secretary John Kelly in coming days, although the administration will not necessarily take actions it recommends.

The plan lays out what it would take to seal the border in three phases of construction of fences and walls covering just over 1,250 miles (2,000 km) by the end of 2020.

With 654 miles (1,046 km) of the border already fortified, the new construction would extend almost the length of the entire border.

Many cost estimates and timelines have been floated since Trump campaigned on the promise of building a wall. The report seen by Reuters is the work of a group commissioned by Kelly as a final step before moving forward with requesting U.S. taxpayer funds from Congress and getting started on construction.

A DHS spokeswoman said the department does “not comment on or confirm the potential existence of pre-decisional, deliberative documents.”

A White House spokeswoman said it would be “premature” to comment on a report that has not officially been presented to the president.

Source: REUTERS