South Korean intelligence has suggested that some North Korean military units, including generals sent to Russia, may have moved to the battlefield to fight Ukraine.

The National Intelligence Service informed parliamentarians of its analysis on Tuesday.

A lawmaker at the conference quoted the agency as saying that the Russian military was teaching its terminology to North Korean soldiers. But agency officials said the two sides appeared to have difficulty communicating.

The briefing discussed a recent report that North Korean Foreign Minister Choe Son Hui was traveling to Russia for an official visit.

The agency said the visit was likely to discuss whether Pyongyang would send additional troops and how to manage other countries’ opinions regarding the deployment.

Agency officials also assessed the North’s failed launch of a military reconnaissance satellite in May.

They said preparations were apparently being made for another attempt at military cooperation with Russia.

Officials said they would continue monitoring in light of Pyongyang’s possible seventh nuclear test after next week’s U.S. presidential election.