The director of the National Security Agency, Keith Alexander, will hold a rare classified briefing for the U.S. Senate on Thursday to list details of terror plots he says were averted by the agency’s covert surveillance programs, which were publicized recently by Edward Snowden, an analyst who used to be employed by an NSA defense contractor.

General Alexander’s offer to privately brief the senators is seen as part of the efforts by President Barack Obama’s administration to defend the surveillance programs, as members of Congress expressed concerns that the programs amounted to “spying on Americans.”

The NSA chief’s promise preceded Snowden’s revelation on Wednesday that the spy agency was snooping on thousands of global computer networks, including hundreds in China and Hong Kong.

Snowden’s claims prompted China’s state-run media to warn that U.S. government-sponsored digital spying on Chinese targets “is certain to stain Washington’s overseas image and test developing Sino-U.S. ties,” the China Daily said on Thursday. “Observers said how the case is handled could pose a challenge to the burgeoning goodwill between Beijing and Washington given that Snowden is in Chinese territory and the Sino-U.S. relationship is constantly soured on cybersecurity.” 

Chinese Foreign Ministry Spokesperson Hua Chunying, when asked if there had been any communication between Washington and Beijing regarding Snowden’s extradition, said: “I have no information to offer.”

Addressing Snowden’s claims that the NSA hacked Chinese networks, Hua reiterated China's official stance that it has been a victim of cyberattacks, Agence France-Presse reported.

“We have repeatedly said that cybersecurity is a global issue. Like other countries, China also faces severe threats of cyberattacks,” she said. “We are opposed to all forms of hacker and cyberattacks. We also think that adopting double standards is not beneficial to an appropriate resolution” of the issue.

Cybersecurity was one of several issues on the agenda during last week’s summit between Obama and his Chinese counterpart, Xi Jinping, in California.