Moscow said Tuesday it had seized the war-battered mining town of Selydove in eastern Ukraine where Kyiv's forces are buckling and as concern grows in Kyiv and abroad over North Korea's expanding military ties with Russia.
The Kremlin's forces have been advancing rapidly across the sprawling eastern front where exhausted and outgunned Ukrainian troops are having to cede ground, appealing for more Western aid.
Russia's claims that its troops had captured four new settlements in the industrial Donetsk region came as Ukrainian leader Volodymyr Zelensky and South Korean's president agreed deeper security cooperation after allies said thousands of North Korean troops were transferred to Russia to aid its offensive.
The Russian defence ministry said its forces had "fully liberated" Selydove, a town of Soviet-era buildings whose estimated population of around 21,000 people have fled from Moscow's drone and rocket attacks.
Moscow also said it had wrested control of the nearby villages of Bogoyavlenka, Girnyk and Katerynivka, also in the Donetsk region, which President Vladimir Putin claimed was formally part of Russia in late 2022, the year Moscow invaded.
The gains announced by Moscow on Tuesday are just the latest in a string of Russian advances that have gained momentum since February with the collapse of Ukraine's defences in the stronghold town of Avdiivka.
Russia has advanced 478 square kilometres (185 square miles) in October alone -- a record since March 2022 -- according to an AFP analysis of data from the American Institute for the Study of War.
Two-thirds of the Russian gains -- or 324 square kilometres -- were in the Donetsk region.
The Russian advances came as Zelensky said he had discussed the deployment of North Korean troops to aid Russia with South Korea's president, Yoon Suk Yeol.
Both countries, along with leaders of the NATO military alliance and the United States, are sounding the alarm over the transfer of some 10,000 North Korean troops to Russia.
"The conclusion is clear: this war is becoming internationalised, extending beyond two countries," Zelensky told the South Korean leader, according to a readout of the call released by Kyiv.
Yoon meanwhile said the involvement of North Korean troops in the Ukraine conflict was "unprecedented and dangerous" and warned about the potential transfer of sensitive military technology and combat experience from Moscow to Pyongyang.
Ukraine will host a delegation from South Korea to discuss the escalation in the near future, a high-ranking official at the Ukrainian presidency said.
"We expect to hear some sensitive details that cannot be conveyed over the phone. It's clear that we have to work more together in the face of what Pyongyang is doing," the official told AFP.
At the same time, North Korean Foreign Minister Choe Son Hui arrived in the far eastern Russian city of Vladivostok, TASS state news agency reported, citing a diplomatic source, who said that "tomorrow she will be in Moscow".
Neither Putin nor Pyongyang has denied North Korean troops are in Russia.
Zelensky meanwhile was visiting Iceland to rally allies around his "victory plan", which stipulates an immediate invitation for Ukraine to join NATO.
Zelensky was also expected to appeal to Nordic leaders for more military aid and air defence systems.
Hours before Moscow announced its alleged advances in eastern Ukraine, its aerial bombardments killed four people in Ukraine's second-largest city of Kharkiv -- around 30 kilometres (18 miles) from the Russian border -- the mayor said.
Mayor Igor Terekhov said nearly two dozen buildings were destroyed or damaged in the attack around 0000 GMT.
It came just after a separate strike damaged the Derzhprom, a modernist structure considered to be one of the first Soviet skyscrapers.
In the southern region of Kherson, Russian shelling killed a 62-year-old man, regional authorities said.
