[WASHINGTON] Donald Trump plans to unilaterally shift nearly US$7 billion in federal funds to construct physical barriers along the US-Mexico border, according to a White House official, a maneuver that risks provoking a lengthy legal battle over presidential powers.

The president will invoke an emergency declaration to redirect some of the funds and ordinary executive authority to tap other money, all of which has been approved by Congress for other purposes, said the official, who spoke on condition of anonymity.

The official declined to be identified because the decision hasn't been announced and wouldn't describe the funding sources Mr Trump plans to tap.

The additional funding would come on top of US$1.375 billion for 88.5km of border fencing contained in a spending measure Trump is poised to sign Friday, bringing the total above US$8 billion. The strategy avoids another politically risky government shutdown while allowing him to show his political supporters he has the will to build the wall.

BLOOMBERG