The head of U.S. intelligence released new details on Saturday about the federal government’s secretive program to monitor Internet users.

Director of National Intelligence James Clapper denied that the program, called PRISM, “unilaterally” obtains information from the servers of U.S. Internet companies.

“PRISM is not an undisclosed collection or data mining program,” Clapper said in a statement. “It is an internal government computer system used to facilitate the government’s statutorily authorized collection of foreign intelligence information from electronic communication service providers under court supervision, as authorized by Section 702 of the Foreign Intelligence Surveillance Act (FISA).”

He said that the Internet companies provide user data to the National Security Agency only after receiving an order approved by a secret FISA court.