Cyberattacks and cyberespionage have replaced terrorism as the top threat facing the United States, the US spy chief said in a report on Tuesday.
China and Russia are two of the most "advanced cyberactors" but are unlikely to launch an attack, James Clapper, the director of national intelligence, said in an annual assessment prepared for lawmakers.
The threat of a digital assault that could cripple a regional power network is genuine but remains a "remote" possibility, he said.
Unlike previous reports, the assessment ranked cyberattacks first on a list of transnational threats, devoting more words to digital hacking and cyberspying than to Islamist extremists in Afghanistan.
Analysts noted that Clapper's remarks came in tandem with US allegations that China is a major source of cyberattacks, adding that Washington's increasing attention to Internet security is no more than political posturing.
Meanwhile, US President Barack Obama was scheduled to sit down with corporate heads on Wednesday to discuss efforts to improve cybersecurity in private industries.
The White House said that in the meeting, which was to take place in the Situation Room, Obama planned to discuss efforts to address the cyberthreat and solicit the CEOs' input on how the government and private sector can best work together to improve the country's cybersecurity.
Reuters reported that the presidential meeting was planned amid "rising concern about hacking attacks emanating from China".
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