The Korean Peninsula

Why is Korea divided into North and South?

Japan ruled Korea from 1910 to 1945. When Japan surrendered, the Soviet Union occupied the north and the United States the south. The two halves became separate states in 1948. North Korea invaded the south on June 25, 1950. China sent troops to fight for the north, and the United States led a UN force for the south. About 3 million people died. An armistice stopped the fighting on July 27, 1953, but no peace treaty followed.

The border, the Military Demarcation Line, runs close to the 38th parallel through a demilitarized zone (DMZ) about 4 km wide. For decades both governments said they wanted reunification. North Korea dropped that goal in December 2023 and January 2024, when Kim Jong Un told a party meeting and then parliament that South Korea was a separate, hostile state. In March 2026 he told parliament that North Korea would treat South Korea as "the most hostile state." South Korea's President Lee Jae-myung has offered talks, but North Korea has not agreed to any.

Does North Korea have nuclear weapons?

North Korea has about 60 assembled nuclear warheads, and enough fissile material for at least 90, by the estimates of the Federation of American Scientists (FAS). South Korea's defense minister put the number higher in August 2026, at 80 to 120. North Korea tested six nuclear devices at Punggye-ri between 2006 and 2017. The 2017 test, which North Korea called a hydrogen bomb, had an estimated yield of about 250 kilotons. The IAEA said in September 2026 that North Korea has built a second uranium enrichment plant at Yongbyon.

North Korea has tested missiles with the range to reach the continental United States. The Hwasong-18, a solid-fuel missile first tested in 2023, is estimated to fly about 15,000 km. North Korea last tested a long-range missile, the Hwasong-19, in October 2024. It showed a larger one, the Hwasong-20, at a parade in October 2025 but has not flight-tested it. In 2026 North Korea has fired ballistic missiles more than ten times. A 2022 law allows North Korea to use nuclear weapons first if it judges an attack on its leadership to be imminent.

What is happening at the DMZ in 2026?

On September 21, 2026 two mine blasts in the western part of the DMZ injured three South Korean soldiers who were clearing a patrol route. A joint investigation by South Korea's military and the UN Command found that North Korea had laid the mines south of the Military Demarcation Line about a year earlier. The UN Command ruled on September 30 that the armistice had been violated. South Korea demanded an apology. Kim Yo Jong, Kim Jong Un's sister, called the findings a "conspiratorial farce." On October 26 North Korea's UN ambassador wrote to the Security Council accusing South Korea of fabricating the blast.

North Korea has fortified its side of the border since April 2024 with fences, mines and anti-tank barriers. In August 2026 South Korean troops fired warning shots after North Korean soldiers briefly crossed the Military Demarcation Line on the eastern front. In 2024 North Korea sent thousands of balloons carrying trash into South Korea. North Korea said the balloons answered leaflets that activists in the South sent north.

On October 23 South Korea proposed military talks about the border line. On October 29 North Korea fired about 10 short-range ballistic missiles into the sea, by the count of South Korea's Joint Chiefs of Staff.

Are North Korean troops fighting for Russia?

South Korea's intelligence service estimates that North Korea has sent at least 16,000 soldiers and engineers to Russia since October 2024. They fought mainly in Russia's Kursk region, which Ukraine entered in August 2024. Russia said in April 2025 that it had retaken the region. About 9,500 North Korean troops were still in Kursk in August 2026, according to Ukraine's military intelligence, and they were not directly involved in fighting Ukraine. South Korea's intelligence service estimates that about 2,000 have been killed.

North Korea confirmed the deployment in April 2025. State media said its forces "participated in the operations for liberating the Kursk areas." On April 26, 2026 Kim Jong Un and the speaker of Russia's Duma, Vyacheslav Volodin, unveiled a monument to the troops in Pyongyang.

Russia and North Korea signed a mutual defense treaty in Pyongyang on June 19, 2024. In 2024 North Korea sent Russia about 9 million artillery and rocket rounds and more than 100 ballistic missiles, according to the Multilateral Sanctions Monitoring Team set up by 11 countries. Russia supplied North Korea with more than 1 million barrels of oil in 2024, above the UN cap of 500,000 barrels a year.