Sixteen US States have sued President Donald Trump over his plan to declare a national emergency to get funding for his controversial wall along the border with Mexico.

The lawsuit came after Trump on Friday declared that he would spend billions of dollars more on border barriers that Congress had granted him.

The National Emergencies Act allows the President to declare a national emergency and unlock a stash of funds by invoking certain statutory authority.

The coalition of 16 states in their lawsuit alleged that the Trump administration’s emergency declaration and diversion of funds are unconstitutional and otherwise unlawful.

The suit, filed in Federal District Court in San Francisco yesterday, argues that the president does not have the power to divert funds for constructing a wall along the Mexican border because it is Congress that controls spending.

The dispute stems from steps Trump said he would take after lawmakers granted him only 1.375 billion dollars for new border barriers. The fund is far short of the  5.7 billion dollars Trump had initially requested.

The lawsuit seeks to block the Trump administration’s emergency declaration, the unauthorised construction of the border wall, and any illegal diversion of Congressionally-appropriated funds, a media release said.