One of the disclosures based on documents leaked by Edward Snowden, the former National Security Agency contractor, prompted the shutdown of a key intelligence program in Afghanistan, the nation’s top spy said Wednesday.

“It was the single most important source of force protection and warning for our people in Afghanistan,” Director of National Intelligence James R. Clapper Jr. said at an intelligence conference.

He was addressing a question about the impact of revelations by Snowden, whose leaks led to a global debate about the proper scope of U.S. surveillance at home and abroad.

Snowden, who now lives in Moscow, was given asylum by the Russian government in 2013.

Although Clapper did not give details, he apparently was alluding to an NSA program that recorded all cellphone calls in Afghanistan.

In March 2014, The Washington Post, citing documents provided by Snowden, reported on a program called MYSTIC, under which the NSA was collecting “every single” phone conversation in a foreign country. The Post, following requests by U.S. officials, withheld the country’s name.

Two months later, the Intercept news site published a similar story about the NSA’s “secretly intercepting, recording, and archiving the audio of virtually every cell phone conversation” in two nations. The site named the Bahamas as one country. It refrained from naming the other, citing concerns that doing so “could lead to increased violence.”

Several days later, the anti-secrecy organization WikiLeaks reported that the country was Afghanistan.

Soon after, “the program was shut down by the government of Afghanistan,” said Clapper, speaking at the Intelligence and National Security Summit in Washington.

“So [Snowden has] done huge damage for our collection,” Clapper said. “Make no mistake about it.”

But Clapper said that some of Snowden’s disclosures had a beneficial effect, an apparent reference to the June 2013 revelation of the NSA’s mass collection of Americans’ phone records — data about the times, dates and durations of phone calls — for counterterrorism purposes. That leak “forced some needed transparency, particularly on those programs that affected the civil liberties and privacy in this country,” he said.

The NSA is ending that program.

“Had that been all he had done, I probably could have understood better and maybe even tolerated,” Clapper continued. “But he exposed so many other things that had nothing to do with domestic surveillance, civil liberties and privacy in this country. He has done untold damage to our foreign collection and analysis capabilities.”

The MYSTIC program in Afghanistan was used for tactical support for troops, such as alerting them to the locations of roadside bombs, said a former U.S. official, speaking on the condition of anonymity to discuss sensitive details. “That was what was key about it,” he said.

Although the use of such a program in a war zone may be understandable, what raised privacy concerns is the prospect of such technology being used in countries for traditional law enforcement. In the Bahamas, the Intercept reported, the capability was used to locate drug traffickers, “a far cry,” the site said, “from derailing terror plots or intercepting weapons of mass destruction.”