North Korean leader Kim Jong-un attends a send-off ceremony before departing Vladivostok on Sunday. (Yonhap)

Leader Kim Jong-un has crossed back into North Korea after a trip to Russia that "opened a new chapter" for the development of the bilateral relations between the two nations, Pyongyang's state media reported Tuesday.

Kim passed through the Tumangang Railway Station on the border between the two countries on early Monday morning, according to the official Korean Central News Agency.

Kim, who left Pyongyang on his armored train on Sept. 10, held a summit with Russian President Vladimir Putin on Wednesday and toured a series of key military sites amid growing concerns of a possible arms deal between the two nations.

The North's leader "further deepened the comradely fellowship and friendly ties with Putin and the government and people of Russia and opened a new chapter of the development of the DPRK-Russia relations," KCNA reported, using the acronym of North Korea's official name.

During talks with Putin, Kim pledged to offer full support for Russia, saying that the Russian army and people will triumph over "evil" forces, in an apparent endorsement of Russia's war in Ukraine.

The North's leader also visited Primorsky Krai, Artyom and other places in the Russian Far East, including a visit to a fighter jet plant in Komsomolsk-on-Amu, while also having talks with Russian Defense Minister Sergei Shoigu in Vladivostok to discuss ways to bolster bilateral military cooperation. (Yonhap)