Grozny, the capital of Russia's Chechen Republic, has come under attack from suspected Ukrainian drones, local media reports say.
A military camp and a base used by the OMON special police unit were the targets of the attack in the early hours of Sunday, the opposition Telegram channels NIYSO and Ostorozhno Novosti said.
Video clips circulating online showed the moment of impact.
Chechen leader Ramzan Kadyrov later confirmed the attack but said only one of the three drones had reached its target.
He said there had been no casualties or damage.
"We will respond to any attempt to attack targets on our soil with more precise and harder retaliatory strikes," Kadyrov wrote on Telegram.
It was the third suspected Ukrainian strike since the start of the month on the region, located well to the southeast of Ukraine.
A number of soldiers were injured in a similar attack on a barracks a few days ago.
Kadyrov said at the time he would exact revenge.
Kadyrov is a supporter of Russian President Vladimir Putin and has strongly backed Russia's February 2022 invasion of Ukraine.
Chechnya has also sent troops to assist the Russian forces.
Elsewhere on Sunday, Ukrainian media reported that Ukrainian forces operating behind the lines destroyed a Russian fuel tanker train in the occupied southern Zaporizhzhia region by blasting the track and then using long-range artillery and drones.
Blowing up the track first brought the train of 40 tanker trucks to a halt on an open section of the line, according to the reports which cited the HUR military intelligence service.
The engine and the last truck were then targeted with artillery, before aerial drones set the remaining trucks alight.
The report said that a major rail link would be out of operation for a considerable period.
The Ukrainska Pravda newspaper published a video on X from a reconnaissance drone that it said showed the attack on the train.
