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.

Despite their elite status, North Korea's "Storm" troops were ill-prepared for the war, South Korea's National Intelligence Service said.

North Korea and Russia are deepening their military cooperation, as Pyongyang ramps up the supply of arms to Moscow for its war in Ukraine and receives much needed cash and oil from the Kremlin in return.

"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.

There are risks of North Korea sending additional troops and military equipment to the Russian army,” Zelensky said. “We will have tangible responses to this.”

The South's Joint Chiefs of Staff (JCS) on Monday said at least 100 North Korean soldiers have died while another 1,000 suffered injuries in the bordering Kursk region, where Moscow's forces have been battling a Ukrainian ground incursion since August.

Ukrainian President Volodymyr Zelenskiy said on Monday that more than 3,000 North Korean soldiers have been killed and wounded in Russia's Kursk region and warned that Pyongyang could send more personnel and equipment for Moscow's army.

In Trump-led armistice talks, the Hermit Kingdom may want a seat at the table.

Western diplomatic sources in Moscow told NHK in mid-December that the idea to send North Korean troops to Russia originated in Pyongyang, not Moscow.

At least one person killed and six wounded as Putin launches more than 70 missiles at Ukraine on Christmas Day

North Korea has supplied Russia with thousands of troops to fight against Ukraine, intelligence officials said, but old footage that has resurfaced on social media does not show the funeral of a general deployed by Pyongyang to lead its troops in the ongoing invasion.