The launch event came as U.S. Secretary of State Antony Blinken was visiting Seoul for talks with South Korean allies over the North Korean nuclear threat and other issues.

North Korea test fires a ballistic missile as Blinken visits Seoul, where he warned that Putin could provide Kim Jong Un with advanced space technology.

South Korea's military said on Monday it has detected signs of North Korea preparing to send more troops and weapons, including suicide drones, to Russia to support its war against Ukraine.

Ukrainian President Volodymyr Zelensky recently said there have been over 3,000 North Korean casualties in Kursk. South Korea reported over 1,000 casualties last week. Newsweek has not verified either figure. Neither Pyongyang nor Moscow has acknowledged the presence of North Korean troops in Russia.

Leaked Russian military documents reveal plans to target civilian infrastructure like nuclear power plants and tunnels, raising concerns about potential war crimes.

"Through various sources of information and intelligence, we assess that North Korean troops who have recently engaged in combat with Ukrainian forces have suffered around 1,100 casualties," the JCS said in a statement.

“In battles yesterday and today near just one village, Makhnovka, the Russian army lost up to a battalion of North Korean infantry soldiers and Russian paratroops,” Mr Zelensky said in his nightly address yesterday, calling the losses “significant.”

North Korea has fired a ballistic missile into the sea at the same time the top United States diplomat was holding meetings in the South Korean capital, Seoul. South Korea’s military said the missile was launched eastward at about noon (03:00 GMT) shortly after US Secretary of State Antony Blinken met with South Korean Acting President Choi Sang-mok.

Russian gas is no longer flowing to EU states through Ukraine following the expiration of a five-year deal, closing an energy route that has existed since the end of the Soviet Union in 1991. President Volodymyr Zelensky said the move means Russia can no longer “earn billions on our blood”.

South Korea's foreign reserves rose from a month earlier in December but reached the lowest level in five years in terms of year-end reading, central bank data showed Monday. The country's foreign reserves came to $415.

Taiwan suspects that China was behind the cutting of an international undersea telecom cable early Friday morning.