Seoul, May 12 (IANS) South Korea's spy agency on Sunday said it is looking into suspicions that North Korean weapons made in the 1970s have been supplied to Russia for its war in Ukraine amid deepening military cooperation between Pyongyang and Moscow.

The remark by the National Intelligence Service (NIS) came in response to a recent report by a local media outlet that 122 mm artillery shells manufactured in the North in the 1970s appeared to be among the weapons that Russia used in its ongoing war against Kyiv, Yonhap news agency reported.

"The NIS is analysing the relevant circumstance in detail and also continues to track overall military cooperation between North Korea and Russia," the spy agency said.

Photos released by a Ukrainian photographer last year showed Korean letters inscribed on rocket shells. Experts said they were likely 122 mm multiple rocket launcher shells.

South Korea's Defense Minister Shin Won-sik has also estimated the North to have shipped around 6,700 containers to Russia since a summit between their leaders in September, which are enough to accommodate approximately three million rounds of 152 mm artillery shells or 500,000 rounds of 122 mm artillery shells.

The NIS also said it is closely monitoring the possibility of illicit shipment of missile parts to North Korea amid concerns it may be procuring such parts to develop new weapons.

On Saturday, North Korea said that it would deploy a new 240 mm multiple rocket launcher to its military starting this year, a day after leader Kim Jong-un oversaw a test-firing of controllable shells for "the technically updated version" of the 240 mm multiple rocket launcher system, according to state media.