North Korean leader Kim Jong Un returned home by train on Sunday, according to Russian news agencies, following a week-long visit to Russia that included talks with President Vladimir Putin about closer military and other cooperation, news agency Reuters reported. Kim was seen strolling down a red carpet to his railway carriage in the Russian Far Eastern city of Artyom, waving goodbye to the strains of a military band, according to a video released on Sunday by Russia's state-run RIA news agency.
Artyom is roughly 254 kilometres (159 miles) from Khasan station, which is located on Russia's border with North Korea.
The trip by North Korea's leader, who rarely leaves the country, heralds "a new heyday of friendship, solidarity, and cooperation in the history of the development of relations between the DPRK and Russia," according to the North Korean state news agency KCNA, which uses the initials for the Democratic People's Republic of Korea.
As Russia accelerates its invasion of Ukraine and North Korea, a secretive communist state, pursues missile and nuclear development, the United States and its allies are concerned about growing military connections between the two neighbours.
South Korea and the United States said military cooperation between North Korea and Russia would violate United Nations sanctions against Pyongyang and that the allies would guarantee there was a cost.
In written replies to the Associated Press on Sunday, South Korean President Yoon Suk Yeol termed such a military alliance "illegal and unjust," and said the international community will "unite more tightly" to deal with growing relations between Moscow and Pyongyang.
Yoon will go to New York for the United Nations General Assembly on Monday.
Russia has gone out of its way to publicise Kim's visit, throwing clues about the possibility of military collaboration with North Korea, a country created in 1948 with Soviet Union support.
On Saturday, Kim met with Russian Defence Minister Sergei Shoigu, who demonstrated nuclear-capable strategic bombers, hypersonic missiles, and warships to the North Korean leader.
Kim and Shoigu "exchanged their constructive opinions on the practical issues arising in further strengthening the strategic and tactical coordination, cooperation and mutual exchange between the armed forces of the two countries and in the fields of their national defence and security," KCNA said on Sunday, Reuters reported.