The director of national intelligence has apologized in writing for not telling the truth to Congress about the intelligence community’s collection of massive amounts of data on millions of Americans — a falsehood exposed publicly by Edward Snowden.

The Office of the Director of National Intelligence released the letter Tuesday from Director James R. Clapper Jr., dated June 21 to Intelligence Chairwoman Dianne Feinstein, D-Calif., and apologizing for providing false testimony to a question from Sen. Ron Wyden, D-Ore., at a March panel hearing about the extent of data collection on Americans.

“My response was clearly erroneous — for which I apologize,” Clapper wrote in the letter, which was first quoted by The Washington Post.

His false answer was inadvertent, he said, and he noted his nearly 50 years in government service.

“Mistakes will happen, and when I make one, I correct it,” he wrote.