The South Korean spy agency believes up to 10,000 members of North Korean forces could be deployed in Russia’s war on Ukraine by December, according to vice chairs of the National Assembly intelligence committee on Wednesday.

“To date around 3,000 North Korean soldiers have been sent to Russia, with an additional 1,500 to be dispatched sometime soon. By December, the number of soldiers dispatched is expected to total 10,000,” Rep. Park Sun-won told reporters after he was briefed by the National Intelligence Service director Cho Tae-yong.

According to Park, the NIS said the North Korean soldiers who had already arrived in Russia were mainly members of Pyongyang’s special forces.

While the NIS does not think North Korean soldiers are on the battlefields yet, Kim Jong-sik, one of the top North Korean missile development engineers, was spotted close to the Ukrainian frontline in early August, the lawmaker said.

Citing the NIS, he said North Korean authorities are discreet about sending forces to fight with Russia and separating families of soldiers who left for the war to prevent the news from spreading. Their families were being moved for about two weeks to suppress possible turmoil among residents.

The lawmaker said the Russian military, meanwhile, is recruiting large numbers of Korean interpreters. North Korean troops who are being trained in Russia are said to have a lack of understanding of modern warfare such as drone strikes. The NIS suspects large numbers of casualties to arise once they are put to war.

In return for providing troops the support North Korea is expected to receive from Russia is expected to be largely economic. Russia is thought to have paid North Korea a certain amount for the number of troops sent. The total sum, which the NIS did not disclose at the moment, was significant, the lawmaker added.