North Korea displayed what appeared to be new long-range and submarine-based missiles on the 105th birth anniversary of its founding father, Kim Il Sung, as a nuclear-powered US aircraft carrier group steamed towards the region.
A US Navy attack on a Syrian airfield this month raised questions about US President Donald Trump's plans for reclusive North Korea, which has conducted several missile and nuclear tests in defiance of UN and unilateral sanctions, regularly threatening to destroy the United States.
North Korean leader Kim Jong Un, Kim Il Sung's grandson, looking relaxed in a dark suit and laughing with aides, oversaw the huge parade on the "Day of the Sun" at Pyongyang's main Kim Il Sung Square.
Goose-stepping soldiers and marching bands filled the square, next to the Taedonggang River that flows through Pyongyang, in the hazy spring sunshine, followed by tanks, multiple launch rocket systems and other weapons.
Single-engine propeller-powered planes flew in a 105 formation overhead.
Unlike at some previous parades attended by Kim, there did not appear to be any a senior Chinese official in attendance. China is North Korea's lone major ally but has spoken out against North Korea's missile and nuclear tests and supported U.N. sanctions.
The North has said it has developed and would launch a missile that can strike the mainland United States but officials and experts believe it is some time away from mastering all the necessary technology.
Weapons analysts said they believed some of the missiles on display were new types of intercontinental ballistic missiles (ICBM).
North Korea showed two new kinds of ICBM enclosed in canister launchers mounted on the back of trucks, suggesting Pyongyang was working towards a "new concept" of ICBM, said Melissa Hanham, a senior research associate at the U.S.-based Middlebury Institute of International Studies at Monterey, California.
"However, North Korea has a habit of showing off new concepts in parades before they ever test or launch them," Hanham said.
"It is still early days for these missile designs".
North Korea, still technically at war with the South after their 1950-53 conflict ended in a truce but not a treaty, has on occasion conducted missile or nuclear tests to coincide with big political events and often threatens the United States, South Korea and Japan.
It warned the United States that any provocation would be met with retaliation.
"All the brigandish provocative moves of the U.S. in the political, economic and military fields pursuant to its hostile policy toward the DPRK will thoroughly be foiled through the toughest counteraction of the army and people of the DPRK," the North's KCNA state news agency said, citing a spokesman for the General Staff of the Korean People's Army.
DPRK stands for the official name of North Korea, the Democratic People's Republic of Korea.
"Our toughest counteraction against the U.S. and its vassal forces will be taken in such a merciless manner as not to allow the aggressors to survive."