U.S. Vice President Mike Pence said Sunday that North Korea's "provocation" underscored the risks faced by American and South Korean service members, hours after the North conducted a failed missile launch shortly before Pence's arrival.
"The North attempted to launch a missile, but we presume that the launch ended in failure", a JCS official said, declining to be named.
The North has in turn warned of a nuclear strike against the United States if provoked.
North Korean soldiers also exhibited large rockets covered by canisters which were rolled out in two different types of transporter erector launcher trucks, or TELs.
South Korea, which hosts 28,500 US troops to help counter the threats, warned of punitive action if the launch led to further provocations such as a nuclear test or a long-range missile launch.
"The president and his military team are aware of North Korea's most recent unsuccessful missile launch".More news: Showers, storms in area today
China has spoken out against North Korea's missile and nuclear tests and has supported United Nations sanctions.
The NSC also discussed how to cope with a possible flood of North Korean refugees into Japan, among whom might be spies and agents, Japanese media reported. He has repeatedly said if China, North Korea's dominant trading partner, is unwilling to do more to pressure the North, the US might take the matter into its own hands.
According to the statements, "Japan does not tolerate repeated provocations like this by North Korea", and protested to the North over the action. Last year, Pyongyang attempted to launch a Musudan missile on April 15, an auspicious date on which millions celebrate Kim II Sung's birthday. This matters because while North Korea regularly launches short-range missiles, it is also developing mid-range and long-range missiles meant to target US troops in Asia and, eventually, the USA mainland.
China, North Korea's most important ally and key provider of food and fuel aid, has sought to cool tensions over Pyongyang's nuclear weapons and missile programs, repeatedly calling for dialogue.
"If the U.S. provokes recklessly, the revolutionary forces will take an annihilating strike", Choe Ryong Hae, a senior regime official, said in a speech at the parade.
President Donald Trump was uncharacteristically quiet about the failed launch of a North Korean missile from the country's east coast. His visit comes just after a failed missile launch by the North. He will also aim to reassure allies in South Korea and Japan that the USA will take appropriate steps to defend them against North Korean aggression. Mr Kim's regime has test-fired ballistic missiles five times this year in his quest to develop a device that can carry a nuclear warhead to North America.