U.S. Defense Secretary Ashton Carter, who arrived in South Korea on Thursday, says Pyongyang's recent missiles tests are a reminder of how dangerous the situation is on the Korean peninsula.
Speaking at Yokota Air Base in Japan before departing for South Korea, Carter told reporters he was "flattered" if the North Korean missile launches were meant to be a "welcome message" for him.
The short-range missiles were launched this week into the sea off North Korea's west coast. North Korea also fired four missiles in a similar test last Friday.
It is not unusual for the North to conduct such tests ahead of visits to the region by U.S. officials or during moments of heightened tension with its foe, South Korea.
Seoul's defense ministry on Thursday called this week's test routine and said the projectiles did not represent a serious security threat to South Korea.
South Korean officials have also said the launches appear to be a response to the ongoing Foal Eagle joint military exercise between the U.S. and South Korea.