Engineers said to be supporting missile launches and reports of North Koreans killed near Donetsk

North Korean military engineers have been deployed to help Russia target Ukraine with ballistic missiles, and North Koreans operating in occupied areas of Ukraine have already been killed, senior officials in Kyiv and Seoul said.

There are dozens of North Koreans behind Russian lines, in teams that “support launcher systems for KN-23 missiles”, a source in Ukraine told the Guardian.

Kim Jong-un, the North Korean leader, last year travelled to Russia for a summit with Vladimir Putin where the two men bolstered their deepening ties with a secret arms deal.

Pyongyang’s ammunition shipments were vital in allowing Russian forces to advance in a grinding war of attrition in eastern Ukraine this summer. But it appears increasingly clear that the agreement went beyond supplying materiel.