US group: NKorean sub equipped to fire missiles

WASHINGTON — Recent satellite imagery appears to show that a North Korean submarine is being equipped to fire missiles.

The finding poses a potential new threat to North Korea's neighbors. It's being published Thursday by 38 North, the website of the U.S.-Korea Institute at the Johns Hopkins School of Advanced International Studies.

It comes as Washington ratchets up sanctions following a destructive hacking attack against Sony Pictures.

North Korea already has an arsenal of land-based ballistic missiles. South Korea's Defense Ministry reported this week that the North may now have the ability to strike the U.S. mainland, and is advancing in efforts to miniaturize nuclear warheads.

Missiles fired from submarines could be harder to detect before launch, but the institute says developing that capability will be expensive and time-consuming.