China’s Defence Ministry spokesman Geng Yansheng says the United States is worsening tensions over cyber-security with its updated cyber-strategy – whereby the US military is now able to retaliate against hackers with cyber-weapons. Reuters reports Geng saying: “This will further exacerbate contradictions and up the ante on the Internet arms race. We are concerned and worried about this.”

China has often been accused of hacking and stealing IPs from the US, a charge it denies, describing the criticism as hypocritical given the NSA’s Prism surveillance programme.

Reacting to the ejection of Russian-based hackers in unclassified parts of the Pentagon’s networks this month, US Defense Secretary Ash Carter referenced the new Pentagon cyber-strategy saying: “Adversaries should know that our preference for deterrence and our defensive posture don’t diminish our willingness to use cyber-options if necessary.”

On adversaries, the document said: “Russian actors are stealthy in their cyber-tradecraft and their intentions are sometimes difficult to discern,” adding that Iran and North Korea had “less developed cyber-capabilities” but overt hostile intent toward US interests.

Earlier this month the US Secretary of Commerce Penny Pritzker, visiting China, was reported by Reuters as saying cyber-security threats must be addressed without creating barriers to trade or investment. He was supporting American Chamber of Commerce criticism of Chinese restrictions on transferring data overseas, saying these would burden firms with building “redundant” data centres in China and hamper domestic companies expanding abroad.

Russia, Germany and Brazil are ratifying or debating similar proposals to keep their citizens’ personal data within the country – a move that the tech industry describes as inefficient, and resulting in fragmentation of the Internet.