North Korea's leader says his military is ready to settle accounts with the U.S., and that has many in Washington nervous.
Kim Jong Un has ordered his military's rocket units to standby to strike U.S. military targets in South Korea and other parts of the Pacific.
South Korea's defense minister says intelligence personnel are closely monitoring the north's missile sites.
Kim Jong Un's latest move is reportedly in response to two U.S. B2 bombers flying a training mission over South Korea this week.
President Obama has stepped up communication with leaders in South Korea and Japan, assuring them that America will do everything possible to stand with its allies.
Last Friday, the U.S. signed a new pact with South Korea allowing American troops to join any military action that is against North Korea.