North Korea might have provided Russia with short-range ballistic missiles and portable anti-aircraft missiles in addition to artillery rounds for its war in Ukraine, a senior South Korean military official said Thursday.

The Joint Chiefs of Staff made the assessment amid concerns over increasing military cooperation between Pyongyang and Moscow following the rare summit between North Korean leader Kim Jong-un and Russian President Vladimir Putin in September.

Military officials estimated about 2,000 containers of military equipment and munitions were shipped from North Korea's northeastern port of Rajin to Vladivostok in Russia's Far East, which is sharply up from 1,000 containers revealed by the White House on Oct. 13 citing satellite imagery taken in September.

The volume is presumed to be capable of loading over 200,000 rounds of 122 mm artillery shells or over 1 million rounds of 152 mm shells, which are used by both countries.

North Korea may have also supplied other weapons to Russia, including T-series tank ammunition, anti-tank guided missiles, rocket launchers, rifles and machine guns and possibly short-range ballistic missiles.

"There have been indications of North Korea's supply of weapons to Russia since mid-2022, and the arms trade via maritime routes increased in August shortly before Kim Jong-un's visit to Russia," the senior official told reporters on background.

In return, Russia may consider providing technological support for North Korea's military satellite, nuclear weapons, as well as fighter jets and air defense systems, according to the official.

"North Korea is expected to initially receive food and fuel to secure the stability of the regime and prepare for the upcoming winter. (The two countries) are expected to additionally discuss military technology transfer, support for the modernization of conventional forces and joint training down the road," the official said.

The South Korean military said it has been closely monitoring the latest development of Pyongyang-Moscow military cooperation in coordination with the United States and vowed to bolster its military readiness against possibilities of the North's advancing weapons program. (Yonhap)