The United States was considering possible options on Thursday in response to a major cyber attack on Sony Pictures blamed on North Korea, amid calls for tougher sanctions on Pyongyang to cut it off from the global banking system.
US experts say options for the Obama administration could include cyber retaliation and financial sanctions but the effect of any response could be limited given North Korea's isolation.
Hackers who said they were incensed by a film on the fictional assassination of North Korea's leader attacked Sony Corp last month, leaking documents that drew global headlines and distributing unreleased films on the Internet. It appeared to be an unprecedented victory for Pyongyang and its abilities to wage cyber warfare.
On Wednesday, Sony canceled next week's theatrical release of the $44 million raunchy comedy, "The Interview," citing decisions by several theater chains to hold off showing the film. The hacker group that broke into Sony's computer systems had threatened attacks on theaters that planned to show it.
US government sources said on Wednesday that US investigators had determined that the attack was "state sponsored" and that North Korea was the government involved.
One US government source said Washington may soon officially announce its conclusion that North Korea was behind the attack.
Political analysts, including Joel Wit of the 38 North Korea project at Johns Hopkins University in Washington, questioned how easy it would be to enforce sanctions and to ensure the support of China, which is North Korea's biggest economic partner, its neighbor and long-time ally.
The United States has a deep economic relationship with China but is sharply at odds with Beijing over Washington's allegations of cyber spying by Chinese state units on US concerns.