North Korea's internet back online after massive cyber outage
Obama's new sanctions against North Korea may prove ineffectiveKCNA via Reuters

Sanctions unveiled by the US against North Korea may add little to existing restrictions. They could be mostly ineffective due to the country's pre-existing international isolation.

The new round of sanctions announced on Friday hit three organizations 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 the US financial system.

But the three North Korean organisation who were targeted for sanction on Friday are already on the US sanctions list. As for the 10 individuals who are to have US assets frozen, AP reports that US officials cannot say whether any of them even have US assets to freeze. Moreover, the US has already imposed strict sanctions upon North Korea over its nuclear program.

Nevertheless, US officials have portrayed the move as a decisive response. "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

"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," Obama wrote in a letter to House and Senate leaders.

North Korea has denied involvement in the cyberattack on Sony. Cybersecurity experts have said it is possible that hackers or disgruntled Sony employees could be responsible. But US officials said that independent experts do not have access to the same classified information as the FBI.

The US is making it clear that retaliation is not limited to those who carried out the attack. The 10 North Koreans singled out for sanctions were not necessarily involved in the attack, according to the US officials.

Some US politicians are calling for a tougher stance. Republican Senator Bob Corker is set to chair the Senate Foreign Relations Committee this year. He said it was time to acknowledge that US policy on North Korea is not working.

Republican House Foreign Affairs Committee Chairman Ed Royce added: "We need to go further to sanction those financial institutions in Asia and beyond that are supporting the brutal and dangerous North Korean regime."