Earlier today Japanese Prime Minister Shinzo Abe warned Parliament that Pyongyang might be able to kill Japan's citizens with poison-tipped missiles.

"There is a possibility that North Korea already has a capability to deliver missiles with sarin as warheads," said Abe. His alarm was echoed by warnings in South Korean media.

Foreign militaries and intelligence agencies have long believed North Korea is deeply involved in chemical weapons research and production. In 2015, the Pentagon told Congress North Korea "likely possesses a CW stockpile" and likely had "the capability to produce nerve, blister, blood, and choking agents."

The Pentagon also said "North Korea probably could employ CW agents by modifying a variety of conventional munitions, including artillery and ballistic missiles."

Abe was going a step further, suggesting the North has now actually weaponized sarin, the same nerve agent used by Syria on civilians last week.

The Japanese are very aware of what nerve agents can do. In 1995, a Japanese cult killed 12 people and made thousands ill on rush-hour trains with sarin. And South Korea, China and Japan are all in range of North Korean non-nuclear missiles.

Without providing specifics, U.S. officials told NBC News that what Abe fears is within the realm of possibility — the North is technically capable of delivering sarin by missile. But the same officials note the U.S. does not have "certainty" on what chemical weapons the North possesses, in what quantities, or whether their chemicals are weaponized, because the North continues to be a "difficult intelligence target."