North Korea may deploy additional troops to Russia to fight in the war against Ukraine in July or August and Pyongyang is continuing to supply arms to Russia, South Korean lawmakers said on Thursday, citing a briefing by the intelligence agency.

The National Intelligence Service (NIS) believes Russia may be readying to mount a large-scale assault against Ukraine in July or August, South Korean member of parliament Lee Seong-kweun told reporters after the closed-door briefing.

“The timing of the additional deployment is that it could be as early as July or August,” Lee said, adding the agency cited a new round-up of troops for the dispatch by North Korea and a recent visit to Pyongyang by a top Russian presidential security official as grounds for its assessment.

In return for North Korea sending artillery ammunition and missiles to Russia, Pyongyang is likely receiving technical advice on satellite launches and missile guidance systems, Lee said, citing the NIS briefing.

After months of silence, both North Korea and Russia have disclosed the deployment of North Korean troops and the role they played in Moscow’s offensive against Ukraine to reclaim the Kursk region.

The two countries said the cooperation is based on the treaty signed by their leaders in June last year that includes a mutual defense pact.