The National Intelligence Service (NIS) says North Korea still lacks the technology to load nuclear warheads onto missiles, despite its recent declaration that it possesses nuclear arms.

The spy agency briefed lawmakers on the North's nuclear development program at a closed-door meeting of the National Assembly's Intelligence Committee on Tuesday.

The agency reportedly said it believes that even if the North had actually succeeded in manufacturing a nuclear arsenal, it would likely comprise only one or two bombs similar to those dropped by U.S. bombers on Hiroshima and Nagasaki during World War II.

Additionally, NIS officials said that the chances North Korea has exported nuclear technology to other countries are low and that there is no possibility of the North shipping such technology overseas for the time being.