North Korean troops are mobilized on the Russian front lines fighting Ukraine, according a South Korean intelligence agency briefing presented to lawmakers Wednesday.

Around 11,000 North Korean troops, many of them from special forces, had already been trained and deployed to Russia’s Kursk region, bordering Ukraine, by late October, Rep. Park Sun-won, the deputy chair of the National Assembly intelligence committee, told reporters. He was citing the National Intelligence Service.

“North Korean soldiers have been assigned to airborne and marine units, training in drone countermeasures and such, and some are believed to be participating in battles,” he said.

Park said the NIS estimates the number of North Korean troops sent to help Russia to be around 11,000, but that the number could rise along with the growing aid of military equipment.

On top of shells and missiles, North Korea has sold to Russia self-propelled 170 mm artillery and 240 mm multiple rocket launchers, which are weapons the Russian military is not familiar with.

“Some additional North Korean personnel may have been sent along to teach Russian soldiers how to operate them,” the lawmaker said.

On Ukraine suggesting the size of the North Korean contingent to be much greater, the NIS told lawmakers it was basing its judgments on intelligence collected from allies as well as South Korea’s own intelligence.

“As Ukraine is in a state of war, they are engaged in psychological warfare just as Russia is. Our intelligence service is making the judgment on a combination of Ukrainian and other sources,” Park explained.

Ukrainian President Volodymyr Zelenskyy said in a video speech to the European Parliament as the war reached 1,000 days on Tuesday that North Korea's military presence in Russia could grow to 100,000

Ponomarenko Dmytro, the Ukrainian ambassador to Seoul, told reporters Tuesday that as many as 15,000 North Korean troops were believed to already be deployed in the war, which is greater than the NIS estimate of around 11,000.

The NIS believes North Korean leader Kim Jong-un may be planning a trip to Russia for a summit with President Vladimir Putin, according to Park. The summit, if it happens, would be a follow-up to a meeting between Putin and North Korean Foreign Minister Choe Son-hui, who was visiting Moscow earlier this month.

“Choe most likely shared something important and sensitive in her discussions with Putin. She extended her stay to hold the meeting with the Russian president, which was not previously planned,” the lawmaker said.