North Korean leader Kim Jong Un threatened to use nuclear weapons to destroy South Korea if attacked, state media reported Friday, after South Korea’s president warned that if the North used nuclear weapons it would “face the end of its regime.”

The fiery rhetoric isn’t new, but comes at a time of tension on the Korean Peninsula and just weeks after North Korean state media released images of Kim visiting a uranium enrichment facility, which produces weapons-grade nuclear materials.

While touring an army base in the western part of the country Wednesday, Kim said if the South were to encroach upon the North’s sovereignty, Pyongyang “would use without hesitation all the offensive forces it has possessed, including nuclear weapons,” the state-run Korean Central News Agency reported Friday.

“If such situation comes, the permanent existence of Seoul and the Republic of Korea would be impossible,” Kim added, using the proper name for South Korea.

Hostilities between the two Korean leaders have been simmering this year as North Korea has appeared to have intensified its nuclear production efforts and strengthened ties with Russia, deepening widespread concern in the West over the isolated nation’s direction.

Kim’s comments appeared to come in direct response to South Korean President Yoon Suk Yeol, who on Tuesday showcased Seoul’s most powerful ballistic missile and other weapons designed to deter North Korean threats during a parade for Armed Forces Day.

North and South Korea have been cut off from each other since the end of the Korean War in 1953, which concluded with an armistice not a peace treaty, leaving the two sides still technically at war.

While both governments had long sought the goal of one day peacefully reunifying, earlier this year Kim announced the North would no longer pursue that aim, calling the South the “principal enemy” and demolishing a monument symbolizing unification.

Last month, North Korean state media released photos of Kim purportedly touring a nuclear facility in a rare glimpse of the nation’s closely guarded weapons program. Experts said the images – which show Kim flanked by men in military uniforms and crisp white lab shirts – underscore North Korea’s growing confidence in its position as a nuclear power.

South Korea has also been building up its arsenal to respond to a potential threat from the North.

On Tuesday, Yoon unveiled the Hyunmoo-5 ballistic missile, which is reportedly capable of penetrating North Korean underground bunkers.

“If North Korea attempts to use nuclear weapons, it will face the resolute and overwhelming response of our military and the SK-US alliance,” Yoon said, in reference to the United States as the country’s key military partner. “The North Korean regime must now break free from the delusion that nuclear weapons will protect them.”

The US flew a B-1B bomber over an Armed Forces Day ceremony on Tuesday in Seongnam, near Seoul, in an apparent show of solidarity.

On Wednesday, Kim called Yoon a “puppet” and said he was an “abnormal man” for bragging about his military might at the doorstep of a nation in possession of nuclear weapons, KCNA reported.

More than a dozen tigers were incinerated after the animals contracted bird flu at a zoo in southern Vietnam, officials said.

State media VNExpress cited a caretaker at Vuon Xoai zoo in Bien Hoa city saying the animals were fed with raw chicken bought from nearby farms. The panther and 20 tigers, including several cubs, weighed between 10 and 120 kilograms (20 and 265 pounds) when they died. The bodies were incinerated and buried on the premises.

“The tigers died so fast. They looked weak, refused to eat and died after two days of falling sick,” said zoo manager Nguyen Ba Phuc.

Samples taken from the tigers tested positive for H5N1, the virus that causes bird flu.

The virus was first identified in 1959 and grew into a widespread and highly lethal menace to migratory birds and domesticated poultry. It has since evolved, and in recent years H5N1 was detected in a growing number of animals ranging from dogs and cats to sea lions and polar bears.

In cats, scientists have found the virus attacking the brain, damaging and clotting blood vessels and causing seizures and death.

More than 20 other tigers were isolated for monitoring. The zoo houses some 3,000 other animals including lions, bears, rhinos, hippos and giraffes.

The 30 staff members who were taking care of the tigers tested negative for bird flu and were in normal health condition, VNExpress reported. Another outbreak also occurred at a zoo in nearby Long An province, where 27 tigers and 3 lions died within a week in September, the newspaper said.

Unusual flu strains that come from animals are occasionally found in people. Health officials in the United States said Thursday that two dairy workers in California were infected — making 16 total cases detected in the country in 2024.

“The deaths of 47 tigers, three lions, and a panther at My Quynh Safari and Vuon Xoai Zoo amid Vietnam’s bird flu outbreak are tragic and highlight the risks of keeping wild animals in captivity,” PETA Senior Vice President Jason Baker said in a statement sent to The Associated Press.

“The exploitation of wild animals also puts global human health at risk by increasing the likelihood of another pandemic,” Baker said.

Bird flu has caused hundreds of deaths around the world, the vast majority of them involving direct contact between people and infected birds.