Russia's state-run TASS news agency says a summit between President Vladimir Putin and North Korean leader Kim Jong Un has started.
The two leaders are believed to be discussing expanding military cooperation between their countries.
TASS had reported that Putin arrived at the Vostochny Cosmodrome space center in Russia's far eastern region of Amur at around 12:30 p.m. on Wednesday. He then greeted Kim, who came to the facility on a special train.
The two leaders later inspected the launch pad of a Soyuz rocket and other facilities at the space center.
Russian diplomatic sources told NHK that they are likely to agree to beef up bilateral cooperation on military technology.
There is a growing view that North Korea will seek Russia's support in acquiring military technologies necessary for nuclear-powered submarines and reconnaissance satellites.