SEOUL (AP) — North Korea confirmed Thursday it has carried out its first underwater-launched ballistic missile test in three years, in an apparent bid to dial up pressure on the United States ahead of a weekend resumption of their nuclear diplomacy.

Wednesday’s test of the Pukguksong-3 missile, which North Korea describes as a submarine-launched ballistic missile, is seen as the North’s most high-profile weapons launch since it began diplomacy with the United States early last year. Some experts say North Korea wants to show to the U.S. what would happen if diplomacy fails again.

The Korean Central News Agency said the missile test in the waters off its east coast was successful and “ushered in a new phase in containing the outside forces’ threat to (North Korea) and further bolstering its military muscle for self-defense.”

It didn’t say which outside forces threaten its security. But North Korea has previously said it was forced to develop nuclear-armed missiles to cope with U.S. military threats.

The KCNA report didn’t elaborate on whether the missile was fired from a submarine, a barge or other underwater launch platform. North Korea-dispatched photos showed the missile rising and spewing bright flames above a cloud of smoke from the sea, but the launch platform was not identifiable.

Kim Dong-yub, an analyst from Seoul’s Institute for Far Eastern Studies, wrote on Facebook that the missile was likely fired from a barge built for an underwater launch. He said the missile is under development and that North Korea must test-fire it from a submarine before deploying it.

South Korea’s Defense Ministry said the North Korean missile traveled about 450 kilometers (280 miles) at a maximum altitude of 910 kilometers (565 miles). Ministry officials said the missile flew higher than any other short-range weapons North Korea test-fired in recent months.

KCNA said the missile was launched in a vertical mode and that its test had no adverse impact on the security of neighboring countries. It said Kim sent “warm congratulations” to the national defense scientific research units involved in the test-firing

If fired at a standard trajectory, Kim, the analyst, said the missile could have travelled 1,500-2,000 kilometers (930-1,240 miles). He said the Pukguksong-3 is a medium-range missile. North Korea hadn’t tested a medium- and long-range missiles since its entrance to talks with the United States.

North Korean and U.S. officials are to meet on Saturday to restart diplomacy on how to end the North Korean nuclear crisis. That diplomacy largely remains stalemated after the February breakdown of a second summit between President Donald Trump and North Korean leader Kim Jong Un in Vietnam.

North Korea has recently warned its dealings with the United States may end if Washington fails to come up with new proposals to salvage the nuclear diplomacy by December.

Pukguksong, or Polaris, is a solid-fuel missile in the North’s weapons arsenal. The country first test-launched a Pukguksong-1 missile from an underwater platform in 2016, and Kim said at the time his military had gained “perfect nuclear-attack capability.” A year later, the North test-launched a Pukguksong-2, a land-based variant of the missile.

North Korea having an ability to fire a missile from a submarine is a threat to the United States and its allies because such launches are harder to detect early enough to respond. The use of solid fuel also increases a weapon’s mobility.

After Wednesday’s launch, the U.S. State Department called on North Korea “to refrain from provocations, abide by their obligations under U.N. Security Council resolutions, and remain engaged in substantive and sustained negotiations to do their part to ensure peace and stability on the Korean Peninsula and achieve denuclearization.”

Japan lodged an immediate protest, saying the missile landed inside its exclusive economic zone for the first time since November 2017.

Story: Hyung-Jin Kim.

WINDSOR LOCKS, Conn. (AP) — A World War II-era plane with 13 people aboard crashed and burned at the Hartford airport after encountering mechanical trouble on takeoff Wednesday, killing seven of them.

The four-engine, propeller-driven B-17 bomber struggled to get into the air and slammed into a maintenance building at Bradley International Airport as the pilots circled back for a landing, officials and witnesses said.

It had 10 passengers and three crew members, authorities said.

Connecticut Public Safety Commissioner James Rovella said hours after the crash that some of those on board were burned, and “the victims are very difficult to identify.”

Some of the survivors of the crash were critically injured, authorities said. One person on the ground was also hurt in the crash and a firefighter involved in the response suffered a minor injury. No children were on the plane.

The death toll of seven could rise, Rovella said. He said some lives were likely saved by the efforts of people including a person who raced to help the victims and people on the plane who helped others to escape the fire by opening a hatch, Rovella said.

“You’re going to hear about some heroic efforts from some of the individuals that were in and around that plane,” he said.

The retired, civilian-registered plane was associated with the Collings Foundation, an educational group that brought its Wings of Freedom vintage aircraft display to the airport this week, officials said.

The vintage bomber – also known as a Flying Fortress, one of the most celebrated Allied planes of World War II – was used to take history buffs and aircraft enthusiasts on short flights, during which they could get up and walk around the loud and windy interior.

“Right now my heart really goes out to the families who are waiting,” Gov. Ned Lamont said. “And we are going to give them the best information we can as soon as we can in an honest way.”

The National Transportation Safety Board sent a team of 10 to investigate the cause of the crash.

The plane was a few minutes into the flight when the pilots reported a problem and said it was not gaining altitude, officials said. It lost control upon touching down and struck a shed at a de-icing facility just before 10 a.m.

The airport – New England’s second-busiest – was closed afterward but reopened a single runway about 3½ hours later.

Flight records from FlightAware shows the plane had traveled about 8 miles (13 kilometers) and reached an altitude of 800 feet (244 meters).

In recordings of audio transmissions, the pilot told an air traffic controller that he needed to return to the airport and land immediately. Asked why, he said: “Number four engine, we’d like to return and blow it out.”

Brian Hamer, of Norton, Massachusetts, said he was less than a mile away when he saw a B-17, “which you don’t normally see,” fly directly overhead, apparently trying without success to gain altitude.

One of the engines began to sputter, and smoke came out the back, Hamer said. The plane made a wide turn and headed back toward the airport, he said.

“Then we heard all the rumbling and the thunder, and all the smoke comes up, and we kind of figured it wasn’t good,” Hamer said.

Antonio Arreguin, who had parked at a construction site near the airport, said he did not see the plane but heard the explosion and could feel the heat from “this big ball of orange fire” about 250 yards (229 meters) away.

The same plane also crashed in 1987 at an air show near Pittsburgh, injuring several people, the Collings Foundation said. Hit by a severe crosswind as it touched down, the bomber overshot a runway and plunged down a hill. It was later repaired.

The crash reduces to nine the number of B-17s actively flying, said Rob Bardua, spokesman for the National Museum of the U.S. Air Force, near Dayton, Ohio.

Boeing-built B-17 Flying Fortresses – 74 feet (23 meters) long, with a wingspan of 104 feet (32 meters) – were used in daylight bombing raids against Germany during the war. The missions were extremely risky, with high casualty rates, but helped break the Nazis’ industrial war machine.

The B-17 that went down was built in 1945, too late to see combat in the war, according to the Collings Foundation.

It served in a rescue squadron and a military air transport service before being subjected to the effects of three nuclear explosions during testing, the foundation said. It was later sold as scrap and eventually was restored. The foundation bought it in 1986.

Story: Chris Ehrmann and Dave Collins. Michael Melia and Susan Haigh contributed to this report.

NEW YORK (Xinhua) — New York City’s landmark Empire State Building was lit with a light show on Monday night in celebration of the 70th anniversary of the founding of the People’s Republic of China (PRC).

When dusk fell, the top two levels of the building started to shine in the Chinese national flag’s red and yellow respectively, with the 204-feet (62-meter) tall antenna lit in red.

The tower lighting also marks the 40th anniversary of the establishment of diplomatic relations between the United States and the PRC.

In a lighting ceremony Monday morning, Chinese Consul General in New York Huang Ping and Empire State Realty Trust Inc. CEO Anthony Malkin flipped a switch to light a model of the Empire State Building.

Huang thanked Malkin and his team for organizing the event, saying the lighting of this iconic building not only serves as an attraction to more tourists from China, but also a “lighthouse” to guide China-U.S. bilateral ties.

The consul general said China sees the United States as “a vital partner in building the community with a shared future for mankind.”

Thousands of tourists from China visit the Empire State Building every month, said Malkin, who just visited China with his family and “learned about the great stories of the strides they (the Chinese people) have made in the last 70 years.”

“All our people benefit from understanding our common goals of harmony and our diverse and rich cultures. When we visit each other, we enjoy that benefit,” he added.

The lights on Monday night could be seen from miles away as the building stands 1,454 feet (443 meters) above Midtown Manhattan. It has been a magnet to global tourists since its completion in 1931.

On Sept. 30, 2009, the Empire State Building was illuminated for China’s National Day for the first time.