Russia escalated its attacks on Kyiv early Wednesday, launching waves of drones and missiles in its first combined aerial assault on the capital in more than 70 days, authorities said.
The broadside came as Washington and Seoul echoed warnings from Ukraine that North Korean troops had begun "engaging in combat operations" alongside Russian forces on the border between the warring countries.
A security source in Kyiv meanwhile told AFP that Ukraine was behind the assassination of a high-ranking Russian naval officer in a car bombing on the annexed Crimean peninsula.
Ukraine's air force said its units had downed four missiles and 37 drones launched by Russia over eight regions of Ukraine overnight and into Wednesday morning.
"It is important that our forces have the means to defend the country from Russian terror," President Volodymyr Zelensky said in response to the attack.
Ukraine has for months been appealing to its Western allies to provide more air-defence systems to fend off Russian attacks on cities and critical infrastructure.
The large-scale bombardment comes at a critical moment on the battlefield. Russian forces are advancing in the east and concerns are growing over future aid for Ukraine after US Donald Trump's victory in presidential elections.
- Explosions in Kyiv, residents shelter -
AFP journalists heard explosions ring out over Kyiv and saw dozens of residents seeking shelter in an underground metro station in the centre of the capital.
Kyiv officials said one man was wounded by falling debris from a downed drone in the suburb of Brovary, while emergency services distributed images of firefighters battling flames at one impact site.
A separate drone attack in the Ukrainian-controlled southern region of Kherson, which the Kremlin claims is part of Russia, killed a 52-year-old woman, the regional head said.
Multiple air raid sirens rang out early Wednesday as authorities said missiles were closing in on Kyiv, which was home to nearly three million people before Russia invaded in February 2022.
"As missiles were approaching Kyiv, the enemy simultaneously launched a ballistic missile attack on the capital. The enemy attack ended with another drone strike," city authorities said.
The attack is the latest in an uptick in escalating strikes on Ukrainian cities, mainly in the south of the war-battered country.
A Russian strike this week on Kryvyi Rig, Zelensky's hometown, killed a 32-year-old mother and her three children.
The Kremlin has repeatedly denied its forces target civilians in Ukraine, a claim its spokesman repeated Wednesday in response to a question over whether Russian forces were working to minimise civilian casualties.
- Crimea assassination -
"Russian forces treat the civilian population with great care," Kremlin spokesman Dmitry Peskov told reporters, adding that Russia would continue its attacks.
Last week, Moscow and Kyiv launched record overnight drone attacks on each other.
Russian ground forces have been making rapid advances in Ukraine's eastern Donetsk region, which the Kremlin claims is part of Russia.
On Wednesday, the Russian defence ministry said its troops had wrested control of the village of Rivnopil, where an estimated 98 people lived before the invasion.
As the Kremlin's forces advance westwards, Kyiv has warned that Russia has amassed a force of 50,000 troops -- including North Korean soldiers -- to push out Ukrainian forces from the Russian border region of Kursk.
In Brussels, US Secretary of State Antony Blinken on Wednesday warned about the deployment of North Korean troops alongside Russian forces fighting on the Ukrainian border.
Blinken said he discussed with NATO chief Mark Rutte the fact that North Korean forces had been "injected into the battle, and now, quite literally, in combat which demands and will get a firm response."
South Korea's spy agency said North Korean soldiers were "engaging in combat" in Kursk, hours after US officials confirmed Pyongyang's troops were actively fighting for Moscow against Ukraine.
The killing of Valery Trankovsky, which was confirmed by Moscow, is the latest in a string of targeted attacks on Russian military officers and pro-Kremlin public figures in occupied Ukrainian territory and within Russia.
Crimea was seized by Russia in 2014 in the wake of pro-democracy protests in Kyiv that sparked fighting in the east with Kremlin-backed separatists.
By Daria Andriievska