North Korea has sent containers to Russia that could hold nearly five million artillery shells, South Korea's defence minister has said.
Speaking to Bloomberg News, Shin Wosnik said that Seoul had detected at least 10,000 shipping containers on their way to Russia.
In return, Russia has reportedly sent North Korea technology to help in its plans to destroy spy satellites as well as conventional arms.
“Putin is expected to seek closer security cooperation with North Korea, especially military supplies such as artillery shells that are necessary to seize a chance to win,” Shin said.
Vladimir Putin is expected to visit Pyongyang in the coming days to meet Kim Jong-un.
The North Korean leader visited Russia last September where he is believed to have agreed a deal with Mr Putin that saw Moscow receive armaments in return for technological support for North Korea's space programme.