Transcript for Ganyard on North Korea: 'The US really has no military options'

Let's bring in ABC news contributor retired ganyard, who travels freakily to Asia. How do you see this test? Hugely provocative indeed. It's a big change in north Korean nuclear technology. In the past, a much simpler form of an atomic bomb. This bomb is five to ten times more powerful than anything they have demonstrated before. It represents a much bigger threat to the region and the United States. We saw that picture of Kim Jong-un with what looked like a small nuclear weapon and a miss missile. What message is he trying to get across? This is most concerning. We believe that they've miniaturized one of their smaller nux. If they're able to miniaturize one of their new thermonuclear devices, that much more of a threat. South Korea is saying they'll discuss ways to deploy the strongest strategic assets. What are they saying? The president of south Kia seems to be signaling that he'll ask the U.S. To redeploy tactical nuke rer weapons. It's cold war weapons. Called a silver bullet. It's a miniature tactical battlefield nuclear weapon. We pulled them off the south Korean peninsula in the early '90s. It sounds like the south Koreans are asking for them to be deployed and ready to go to protection is south Korean people. What are the U.S. Military opgs? They really have none. The costs would be too high in lives on the Korean peninsula. The U.S. Will do back and look at economic sanctions. Prime minister Abe and president trump have talked three times this week. There may be something brewing in the U.N. We may have to learn to live with a nuclearized North Korea. Thank you for joining us, colonel ganyard.

This transcript has been automatically generated and may not be 100% accurate.