U.S. President Donald Trump will sign a long-anticipated executive order on Thursday that aims to shut down the Department of Education, acting on a key campaign pledge, according to a White House summary.

The move is already being challenged by a group of Democratic state attorneys general, who have filed a lawsuit seeking to block Trump from dismantling the department and halt the layoffs of nearly half of its staff announced last week.

Trump and his billionaire adviser Elon Musk have attempted to shut down government programs and institutions such as the U.S. Agency for International Development without congressional approval, but abolishing the Department of Education would be Trump's first attempt to shut down a cabinet-level agency.