Updated

South Korean warships have conducted live-fire exercises at sea. The drills Tuesday mark the second-straight day of military swagger from a nation still rattled by the North's biggest-ever nuclear test.

Pyongyang said it conducted a test of a hydrogen bomb Sunday. It puts the North a huge step forward in its push for viable nuclear missiles capable of hitting the United States.

But it has also resulted in South Korea boosting its own military capabilities. Washington and Seoul agreed to lift warhead restrictions on South Korean missiles that the allies had previously agreed upon.

This allows for the development of more powerful weapons needed to improve Seoul's pre-emptive strike capabilities against the North.

Seoul says North Korea appears to be planning a future missile launch, possibly of an ICBM.