North Korea's claim Wednesday to have successfully tested a hydrogen bomb ignited "another tinderbox in the world besides the Middle East," said former ambassador to the United Nations Bill Richardson.
While doubting the detonation was actually as powerful as a hydrogen bomb, he pointed out on CNBC's "Squawk Box" this was Pyongyang's fourth nuclear test since 2006. "I don't think this was a hydrogen bomb," Richardson said. "It was apparently six kilotons. A hydrogen bomb is 20."
The office of a South Korean lawmaker on the parliamentary intelligence committee reported the six-kiloton size of the test, roughly the same size as the North's last test, which was equivalent to six to seven kilotons of TNT.
"It basically says to the world, 'Hey we're around. You can't just deal with Iran and the Middle East,' " Richardson said. "And it also says to the world, 'We're going to develop a nuclear arsenal regardless ... and it's not going to be a bargaining chip.' "
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Richardson, who served as energy secretary during President Bill Clinton's administration, stressed the gravity of North Korea's aggression. "This is a very serious situation. Some real high-level diplomacy — mainly the U.S., China, and now Russia, which is another friend of North Korea — need to engage more than we have."
The flare-up in Pyongyang comes at a complex time on the world stage, with Saudi Arabia cutting diplomatic ties with Iran after the storming of the Saudi embassy in Tehran over Riyadh's execution of a Shiite Muslim cleric accused of terrorism.
Richardson said the Saudis, a Sunni power, "shouldn't have executed the cleric" because they should have anticipated the sectarian outrage.
Defending the move, Adel al-Jubeir, the Saudi minister of foreign affairs, said in a CNBC interview on Tuesday that Iran executes "hundreds of people" annually, actively supports terrorists and sows conflict throughout the Mideast.
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"We're not talking about human rights champions on either side," Richardson said Wednesday. "But we need Saudi Arabia to build a coalition of Arab countries to form ground troops against ISIS. That should be our main objective."
A former governor of New Mexico, Richardson also unsuccessfully sought the 2008 Democratic presidential nomination.
— Reuters contributed to this article.