The United States says its new round of sanctions against North Korea is just the opening salvo in its response to an unprecedented cyber-attack on Sony Pictures Entertainment.
Yet there may be little else America can do to further isolate a country that already has few friends in the world.
Even the latest sanctions, handed down by President Barack Obama in an executive order, may not sting quite as badly as the US would have hoped because North Korea is already under a strict sanctions regime imposed by America over its nuclear programme.
The new round of sanctions hit three organisations closely tied to the North's defence apparatus, plus 10 individuals who work for those groups or for North Korea's government directly.
Any assets they have in the US will be frozen and they will be barred from using America's financial system.
But all three groups were already on the US sanctions list, and officials could not say whether any of the 10 individuals even had assets in the US to freeze.
Nevertheless American officials portrayed the move as a swift and decisive response to North Korean behaviour they said had gone far over the line. Never before has the US imposed sanctions on another nation in direct retaliation for a cyber-attack on a company.
"The order is not targeted at the people of North Korea, but rather is aimed at the government of North Korea and its activities that threaten the United States and others," Mr Obama said in a letter to House of Representatives and Senate leaders.
North Korea has denied involvement in the cyber-attack, which led to the disclosure of tens of thousands of confidential Sony emails and business files, then escalated to threats of terrorist attacks against cinemas.
Many cyber-security experts have said it is entirely possible that hackers or even Sony insiders could be the culprits and questioned how the FBI could point the finger so conclusively.
Senior US officials repeated their assertion that North Korea was responsible and said independent experts did not have access to the same classified information as the FBI.
With this round of sanctions, the US also put North Korea on notice that sanctions need not be limited to those who perpetrated the attack.
The 10 North Koreans singled out for sanctions did not necessarily have anything to do with the attack on Sony, senior US officials said. Anyone who works for or helps North Korea's government is now fair game - especially Pyongyang's defence sector and spying operations.
But prominent politicians were already calling for an ever harsher stance. Republican senator Bob Corker, who will chair the Senate's Foreign Relations Committee this year, said it was time to concede the US policy on North Korea was not working.
And Republican House Foreign Affairs Committee chairman Ed Royce said: "We need to go further to sanction those financial institutions in Asia and beyond that are supporting the brutal and dangerous North Korean regime."
Mr Obama has said the US is considering whether to put North Korea back on its list of state sponsors of terrorism. Beyond that it is unclear what additional penalties the US has in its arsenal, as there is no appetite for a military intervention.
But the US has said that some elements of its response may not be seen publicly.
The sanctions target the country's primary intelligence agency, a state-owned arms dealer that exports missile and weapons technology, and the Korea Tangun Trading Corporation, which supports defense research. The individuals sanctioned include North Koreans representing the country's interests in Iran, Russia and Syria.
There was no immediate response from North Korea. Sony declined to comment.
While denying any role in a cyber-attack, North Korea has expressed fury over the Sony comedy The Interview, which depicts a fictional assassination plot against North Korean leader Kim Jong Un.
Sony initially called off the film's release after cinemas decided not to show it. After Mr Obama criticised that decision, Sony decided to release the film in a limited number of cinemas and online.
The White House called the sanctions "the first aspect of our response" to the Sony attack, a declaration that raised fresh questions about who was behind a nearly 10-hour shutdown of North Korean websites last week.
The shutdown prompted a blunt response from North Korea's powerful National Defence Commission, which blamed the US and hurled racial slurs at Mr Obama, calling him a reckless "monkey in a tropical forest".