President Donald Trump asserted on Sunday that China was working with the United States on "the North Korea problem", and his vice president told American and South Korea service members that the North's latest "provocation", a failed missile launch shortly before his arrival in Seoul, laid bare the risks they face.
In the event of either a nuclear or a missile test, the US military is likely at a minimum to conduct a show of force, potentially repositioning American forces within South Korea, flying long-range bombers over the southern part of the peninsula or moving ships around in nearby waters.
North Korea's display comes as tensions on the Korean Peninsula have spiked to alarming levels.
North Korean soldiers also rolled out what appeared to be another large rocket covered by a canister.
Trump administration officials describe the situation as more risky than in the past, both because of the progress North Korea has made in its nuclear and missile programs and because of the hostility on both sides.
Trump's decision to order a cruise missile strike on a Syrian airfield this month, in response to what he said was Syria's use of chemical weapons, raised questions about his plans for reclusive North Korea. It's no exaggeration to say that the Chinese are fed up with Kim Jong Un.
That commitment, aides say, will be underscored by Pence's very personal ties to South Korea.
H.R. McMaster indicated that Trump was not considering military action for now, even as a nuclear-powered aircraft carrier strike group was heading for the region. He criticized the new US government under President Donald Trump for "creating a war situation" on the Korean Peninsula by dispatching strategic military assets to the region.
An official from South Korea's Unification Ministry, who spoke on condition of anonymity, citing office rules, confirmed that the man was Kim Won Hong and said his appearance shows he has been reinstated from a "purge state".
Expectations for a nuclear test or a missile launch in the lead-up to Saturday's celebrations in Pyongyang have not come to pass.
The North has said it has developed a missile that could strike the US mainland, but officials say that ability may take more time for development.
However, John Bolton, America's former ambassador to the United Nations, said piling on pressure wouldn't work and that the USA needed China's help to try and bring North and South Korea back together.
Military airplanes flew in formation above Kim Il Sung Square where the day's festivities were held.
As scores turned out to celebrate what would be Kim's 105th birthday, Mr Choe told the packed-out square: "If the United States wages reckless provocation against us, our revolutionary power will instantly counter with annihilating strike, and we will respond to full out war with full out war and to nuclear war with our style of nuclear strike warfare". Solid-fuel missiles can be fired more quickly than liquid-fueled missiles because the fuel is already just hanging out in the missile prior to launch. Also on display was a powerful midrange missile that outside analysts call a "Musudan", and which can potentially reach US air bases in Guam, as well as a new solid-fuel midrange missile that can be fired from land mobile launchers, making them harder to detect before launch.
"It's in their interest to see North and South Korea reunited in a sensible way, that would end the North Korean nuclear weapons program and in my view that's the only way it's going to happen", he said.
Its National Security Council has discussed how to evacuate the roughly 60,000 Japanese nationals living in South Korea and how to deal with a potential influx of North Koreans, according to multiple local reports.
The United States has recently stated several times that they are considering all possible options for action in relation to the DPRK. US satellite imagery suggests the country could conduct another underground nuclear test at any time. At the other end of the spectrum, they looked at the notion of accepting North Korea as a nuclear state.
The North conducted two such tests a year ago alone.