North Korean leader Kim Jong Un expressed admiration for Russia's aviation technology undergoing rapid development, outpacing the outside potential threats, during his visit on Friday to a Russian fighter jet factory, KCNA reported on Saturday.
On Friday Kim inspected the Russian fighter jet factory, which is under Western sanctions, as part of a visit Washington and its allies fear could strengthen Russia's military in Ukraine and bolster Pyongyang's missile programme.
Russian President Vladimir Putin and Kim discussed military matters, the war in Ukraine and deepening cooperation when they met on Wednesday.
Kim met test pilots at the fighter jet fuselage assembly shop and got on an Su-57 to hear a detailed explanation of the technical specifications and flight performance of the fifth-generation fighter jet.
He climbed onto an airliner produced by the plant to learn about its performance and watched the test flight of an Su-35 fighter jet.
The North Korean leader's stay is expected to continue on Saturday, possibly with a visit to the eastern city of Vladivostok and a naval base.
The Kremlin said on Friday that Russia and North Korea had not signed any agreements on military matters or on any other areas during Kim's visit to Russia this week.
South Korea and the US said on Friday that military cooperation between North Korea and Russia was a violation of UN sanctions against Pyongyang, and that the allies would ensure there is a price to pay.