Secretary of Defense Mark Esper approved the construction of 20 miles of the 30-foot high wall that marks the border with Mexico.

The funding for the addition comes from money left over from other Pentagon projects that was redirected, according to Politico’s Aug. 27 report.

These funds were part of a total of 2.5 billion dollars used to build about 134 miles of the physical barrier between the two countries, in Yuma and Tucson in Arizona and El Paso in Texas. Since the real costs were lower than budgeted, the remaining money has been redirected.

Although a controversy arose over the Pentagon’s legal capacity to allocate part of its budget to the construction of the border fence, the Supreme Court approved the use of the funds, while judicial proceedings continue.

The programs previously approved and from which funds were taken to finance the construction of the wall include training Afghanistan security forces, and upgrades to the E-3 aircraft and Minuteman III, as well as savings from lower-than-negotiated contracts for air launch cruise missiles and Predator Hellfire missiles, according to VOA.