U.S. Secretary of State John Kerry has accused China and Russia of "very likely" reading his e-mails.
"It's very possible. ... I certainly write things with that awareness," he said on the CBS Evening News, responding to a question about whether he thought the two countries were reading his e-mails.
"It is very likely. It is not...outside the realm of possibility, and we know that they have attacked a number of American interests over the course of the last days," he said.
"Unfortunately, we're living in a world where a number of countries, the Chinese and Russians included, have consistently been engaged in cyberattacks against American interests, against the American government," Kerry said. "It is an enormous concern."
Russia is the principal suspect in a recent hacking of the White House Joint Chiefs of Staff personal e-mail system.
China is suspected of being behind cyberattacks that stole massive amounts of personal data on federal employees.