American journalist and political commentator Glenn Greenwald has claimed that National Security Agency leaker, Edward Snowden, poses more of a threat to the U.S. than anyone in the country’s history.

Greenwald, whose collaborations with Snowden for The Guardian exposed U.S. surveillance programs, said that as a result, U.S. officials should hope Snowden stays safe because if not, a mass of harmful information would become public.

“Snowden has enough information to cause more damage to the U.S. government in a minute alone than anyone else has ever had in the history of the United States,” Greenwald told the Argentinian newspaper La Nacion.

“If something were to happen, those documents would be made public. This is your insurance policy,” he said.

“The U.S. government should be on your knees every day praying that nothing happens to Snowden, because if something happens, all information will be revealed and that would be their worst nightmare,” Greenwald added.

Greenwald’s interview comes as Snowden remains in the Moscow airport, where he has remained been for almost three weeks.

Bolivia, Nicaragua and Venezuela have offered Snowden asylum, despite intense pressure from the United States.