That's according to Yonhap, Ukrinform reports.
"As for the supply of lethal weapons to the combat zone in Ukraine, it would be a very big mistake. I hope it will not happen," Putin said at a press conference during his visit to Vietnam.
He threatened Seoul with consequences if South Korean weapons were transferred to Ukraine.
"If it does, then we too will then make the respective decisions, which South Korea's current leadership is unlikely to be pleased with," he said.
Read also: Putin's visit to North Korea a significant goodwill gesture towards Kim - ISWAccording to Reuters, Putin said that Russia might supply weapons to North Korea in what he suggested would be a mirror response to the Western arming of Ukraine.
Putin threatened earlier this month that Russia might supply arms to Western adversaries because the West was providing high-precision weapons to Ukraine and giving it permission to fire them at targets inside Russia.
"I said, including in Pyongyang, that we then reserve the right to supply weapons to other regions of the world. Taking into account our agreements with (North Korea), I do not exclude this either," he said.