Billionaire Elon Musk appears to have overstepped his executive branch authority with his Department of Government Efficiency, a federal judge said Tuesday as he indefinitely blocked the dismantling of USAID.

Maryland-based Judge Theodore D. Chuang issued an injunction Tuesday in response to a lawsuit brought by former USAID employees and contractors, who argued Musk’s takeover of USAID—whose functions the Trump administration has largely shut down—was unconstitutional,

U.S. District Judge Theodore Chuang found that the Trump administration and Elon Musk violated the constitutional separation of powers and the Appointments Clause when it ordered the shuttering of the foreign aid agency.