Pyongyang displays military hardware, including apparently new intercontinental ballistic missile

North Korea showed off what appeared to be a new intercontinental ballistic missile, seen here in an image taken from North Korean TV footage, at a military parade in Pyongyang on Saturday, April 15, 2017. 

SEOUL—North Korea showed off what appeared to be at least one new long-range missile at a military parade Saturday, as tensions simmer over the possibility of a military confrontation between the U.S. and North Korea.

The weaponry on show, which appeared to include a newly-modified intercontinental ballistic missile and two types of large launchers with never-before-seen missile canisters, is likely to trigger fresh concerns about the speed with which Pyongyang’s missile program has advanced in recent years.

A spokesman for South Korea’s Ministry of National Defense declined to comment on the possible new military hardware, saying more time was needed to analyze the missiles.

But an expert on North Korean weapons said the new hardware appeared to be far more advanced than expected.

Meanwhile, recent satellite imagery suggests North Korea may be preparing a sixth nuclear test at Punggye-ri, where the recorded blasts have escalated in strength since the first one in 2006.

U.S. and Asian intelligence agencies will be closely analyzing what type of device North Korea detonates, should it move ahead with a test. The U.S. believes North Korea’s first five tests have been plutonium bombs. But if uranium is used in the next test, it could suggest the North has a much larger arsenal than initially believed. Current estimates are that the country has between 20 and 40 atomic weapons.

North Korea has also said it’s seeking to develop hydrogen bombs, which have much larger explosive impact than conventional nuclear weapons.

Last weekend, amid concerns about possible new tests, the U.S. Navy canceled planned port calls in Australia for the USS Carl Vinson and instead sent the strike group, including the aircraft carrier and two guided-missile destroyers, toward the Korean Peninsula.

Separately, U.S. Vice President Mike Pence is due to arrive in Seoul on Sunday for a three-day visit to South Korea, the first stop in a four-country tour that also includes Japan, Indonesia and Australia. Mr. Pence’s visit to Seoul, which will include a meeting with the country’s acting president, is expected to focus on security issues.

North Korea showed off its military hardware Saturday at a parade—presided over by Mr. Kim—to mark the 105th anniversary of the birth of state founder Kim Il Sung. It took place in central Pyongyang before a crowd of foreign journalists and members of pro-North Korea groups from around the world.

The North also paraded two missile canisters that hadn’t been seen before and which appeared to be able to accommodate larger missiles than the North has ever displayed publicly. While the canisters may not contain missiles, experts said the display indicated the North’s intentions to build larger ICBMs.

“A lot of this may be intimidation or bluffing, but it’s potentially a sign of things to come,” Mr. Schmerler said.

North Korea also paraded a submarine-launched ballistic missile and a land-based variant, which it fired into the Sea of Japan during a February summit in Florida between Mr. Trump and Japanese Prime Minister Shinzo Abe.

Ahead of the parade, the North Korean leader arrived in a limousine and walked along a red carpet as soldiers chanted “mansei,” or “long live.” Mr. Kim then appeared on a balcony overlooking Kim Il Sung Square to watch the parade.

North Korea experts monitoring footage of the march said Mr. Kim’s younger sister, Kim Yo Jong, was visible on the stage, as was Kim Won Hong, the head of North Korea’s secret police, who South Korean intelligence said this year had been removed.

The march came a day after Beijing urged the U.S. and North Korea to tone down their rhetoric, saying no one would win if there was a war.

“On the Korean Peninsula issue, it is not the one who espouses harsher rhetoric or raises a bigger fist that will win,” China’s Foreign Minister Wang Yi said Friday.

Meanwhile, China’s flag carrier,  Air China Ltd . , on Friday suspended flights to the North Korean capital. A spokeswoman for the carrier said the cancellation of the flights, which ran three times a week, was temporary and that it would consider passenger demand for future flights.