Ukraine struck Russia's headquarters in occupied Kherson with a barrage of long-range Himars missiles during a meeting of top officials.
Video footage filmed in the aftermath of the strike showed smoke billowing from the roof of the Court of Appeal in the centre of the city, while citizens fled the area.
Pro-Kremlin collaborators had been meeting in the venue, which served as the headquarters of the Moscow-installed occupation authorities in the area, when the rockets hit, according to Russian state media.
Kirill Stremousov, the Russian-installed deputy leader of Kherson, said the Ukrainian strike directly hit his office, with five US-provided High Mobility Artillery Rocket System (Himars) rockets smashing into the area.
The attack appeared to mark a shift in Kyiv's strategy, striking hard at the civilian command hubs of occupation forces that have so far been spared from targeting with long-range munitions.
It came as an explosion in the city of Luhansk killed the prosecutor general of the self-proclaimed Luhansk People's Republic (LPR), the Moscow-backed separatist movement in eastern Donbas.
Western officials have claimed one of the "unheralded successes" of the recent counter-offensives, across the Kherson and Kharkiv regions, had been disrupting Moscow's Russification attempts in its occupied territories.
Alla Barkhatnova, the Kremlin-installed labour minister for Kherson, was injured in the blast, but made a lucky escape when she was shielded from shrapnel by a co-worker. Her driver was one of the collaborators killed, she added.
Ukraine's armed forces refused to take credit for the strike, which was branded a "vile act of terror" by pro-Russian officials in the city.
Two large explosions this morning in Russian-held Ukrainian strongholds Luhansk and Kherson, reports say, targeting administrative offices. Russian state media claims one dead and one wounded in Kherson. Not seeing official reaction from Ukraine so far. pic.twitter.com/6uItbtGk2J
— Matthew Luxmoore (@mjluxmoore) September 16, 2022
Despite Ukrainian silence, the strike appeared to use precise intelligence of the meeting, which was attended by Kremlin-installed military and civilian officials from across the southern region, and employed US-provided Himars, which can hit targets at a range of 50 miles.
"There was smoke and ringing in my ears. I came round when someone pulled me out. A young guy dragged me from the ruins. I'm alive, and back at work. We are tallying our staff," Eketerina Gubareva, the deputy head of Kherson's Russian-controlled city hall, who was caught up in the blast, wrote on the Telegram messaging app.
Kherson was the only regional capital that was captured by Russian forces in the first few days of their invasion in February.
The strategically important city, which borders the illegally annexed Crimea Peninsula, is seen as the ultimate target for Ukraine's southern counter-offensive.
Russia's puppet authorities in Kherson earlier this month shelved plans to hold a sham referendum to annex the city as Ukraine's counter-attack edged closer.
Around the same time as the strike in Kherson, a bomb killed Sergei Gorenko, the LPR's prosecutor-general, in his office, alongside his deputy.
Mykhailo Podolyak, one of Volodymyr Zelensky's closest aides, said Ukraine was not behind the blast, instead blaming an internal mafia dispute.
The Russian-appointed deputy mayor of Berdyansk, in the southern Zaporizhzhia region, and his wife, who was in charge of organising a referendum to join the Russian Federation, were also assassinated near their home.
Oleg Boyko and his wife Lyudmila became the fourth and fifth pro-Russian victims when they were killed on Friday in a blast near their garage, according to local officials.
The attacks will likely unnerve Russia's local proxies in the war-torn country as pro-Kremlin officials are increasingly targeted by Ukraine's armed forces and pro-Kyiv partisans.