A US submarine has arrived in South Korea, amid worries of another North Korean missile or nuclear test.
The missile-armed USS Michigan is set to join an incoming group of warships led by aircraft carrier Carl Vinson.
North Korea is celebrating its army's 85th founding anniversary today.
It marked the event with a large-scale firing drill.
Tensions have risen in the area in recent weeks, with the US and North Korea exchanging heated rhetoric.
The missile-armed USS Michigan is set to join an incoming group of warships led by aircraft carrier Carl Vinson.
North Korea is celebrating its army's 85th founding anniversary today.
It marked the event with a large-scale firing drill.
Tensions have risen in the area in recent weeks, with the US and North Korea exchanging heated rhetoric.
