In what points to a US cyber-attack, North Korea completely lost its connections to the Internet for several hours on Monday after days of unusual instability, according to several Internet monitoring companies.

The loss of access came just days after the FBI accused Pyongyang of hacking into Sony Pictures Entertainment and President Barack Obama declared that the US would carry out an unspecified “proportionate response” against North Korea at “a time and place of our choosing.”

Matthew Prince, founder of US Internet company CloudFlare, told the New York Times that North Korean access was “toast.” He said a large number of connections had been withdrawn, “showing that the North Korean network has gone away.”

Dyn Research analyst Doug Madory told Bloomberg: “The situation now is they are totally offline. I don’t know that someone is launching a cyber-attack against North Korea, but this isn’t normal for them. Usually they are up solid. It is kind of out of the ordinary. This is not like anything I’ve seen before.”

Speaking to the New York Times, Madory said North Korean access first became unstable last Friday before worsening over the weekend and shutting down completely on Monday. “Their networks are under duress. This is consistent with a DDoS attack on their routers,” he said.

A DDoS (distributed denial of service) attack involves bombarding a website or routers with so much Internet traffic that it collapses. North Korea has a limited Internet usage, all of which is routed via neighbouring China, through state-owned China Unicom. The small size of the North Korean networks renders them more vulnerable to attacks.

Arbor Networks scientist Dan Holden cast doubt on US government involvement, saying other hackers could have carried out the attack. No hackers or hacking collectives have claimed responsibility. “If the US government was going to do something, it would not be so blatant and it would be way worse,” Holden told Bloomberg.

In fact, a blatant Internet attack is exactly what the Obama administration would mount to ensure that the message was unmistakeable, not only to the Pyongyong regime, but to other countries, especially North Korea’s neighbour and ally, China.

From the outset, US claims of North Korean hacking of Sony had the character of a deliberate provocation designed to divert attention from the recently released report of the Senate Intelligence Committee on CIA torture, as well as to further demonise the North Korean regime and its leader Kim Jong-un.

Neither the FBI nor the Obama administration has provided a shred of evidence to justify allegations of North Korean hacking. Pyongyang has rejected the claim and offered a joint investigation, while warning of retaliation against any US action over the supposed hacking of Sony Pictures Entertainment.

The New York Times reported on Saturday that Obama had instructed the military’s Cyber Command “to come up with a range of offensive options that could be directed at North Korea.” Under discussion was what “one Defence Department official termed ‘a demonstration strike’ in cyberspace, which could have included targets such as North Korean military facilities, computer network servers and communications networks.”

While the New York Times article claimed that such a strike appeared to have been ruled out, the collapse of North Korea’s Internet links is completely in line with the White House discussion.

The Obama administration has not denied that the US is responsible for shutting down North Korea’s on-line connections. In an email to the media, National Security Council spokeswoman Bernadette Meehan declared she had no information, adding: “If in fact North Korea’s Internet has gone down, we’d refer you to that government for comment.”

US State Department spokeswoman Marie Harf refused to confirm reports that North Korea had lost its access. However, she pointedly drew a connection to Obama’s threat of a “proportionate response,” saying the US would not comment and, “as we implement our responses, some will be seen, some may not be seen.”

Harf drew attention to the UN Security Council debate this week on referring North Korea to the International Criminal Court over human rights abuses, claiming that Pyongyang’s diplomatic activity sought to “avoid scrutiny of I think what anyone would call an atrocious human rights record.” The discussion in the Security Council is part of a US-led campaign that resulted in a UN Human Rights Council commission of inquiry report, which was tabled in February.

While Pyongyang has undoubtedly carried out gross abuses of democratic rights, the US campaign is utterly hypocritical, especially given that a Senate Intelligence Committee report has provided evidence of systematic CIA torture. The demonisation of North Korea over human rights and the allegations of “cyber-vandalism” highlight the accelerating US efforts to isolate and destabilise the Pyongyang regime.

A cyber-attack on North Korea is just one of the “responses” flagged by the Obama administration. On Sunday, Obama announced that he would “review” whether to return North Korea to the US list of state sponsors of terrorism—a move that would compound Pyongyang’s international isolation. President George W. Bush took North Korea off the list in 2008 as part of an agreement with North Korea to dismantle its nuclear programs and facilities. The deal quickly collapsed and Obama has made no attempt to revive it.

Also under discussion are far tougher economic sanctions, including targeted financial and banking restrictions designed to effectively cut off North Korea from the international financial system and drive its unstable economy to the point of collapse. Pyongyang already faces some of the harshest economic sanctions in the world, imposed by the US directly and through the UN Security Council, on the pretext of halting North Korea’s nuclear programs.

The latest intensification of US pressure on North Korea is primarily directed not at Pyongyang, but at Beijing, as part of the Obama administration’s “pivot to Asia” aimed at undermining and militarily encircling China. The Chinese government is acutely sensitive to the danger of a political crisis on its doorstep in North Korea and the prospect of an intervention by the US and its allies.

In a move to involve China directly in the conflict with North Korea, US officials told the New York Times and CNN that Washington had asked China for help in blocking cyber-attacks emanating from North Korea. Chinese Foreign Minister Wang Yi spoke to US Secretary of State John Kerry on Sunday, declaring that Beijing “opposes all forms of cyber-attacks and cyber terrorism.” But Chinese foreign ministry spokesman Hua Chunying cautioned against “making any conclusions” about who was responsible for the Sony hacking.

There is nothing “proportionate” about the US actions against North Korea. Having publicly accused Pyongyang of hacking Sony without any substantiation, the Obama administration is recklessly provoking tensions in North East Asia. The collapse of North Korean Internet connections, which has all the hallmarks of a US operation, threatens to trigger a dangerous spiral of escalation and heighten the risk of conflict.