Ukrainian forces hit an ammunition dump in Crimea, forcing an evacuation of the area and canceling train services, authorities in the annexed province say.
It marks the latest in a series of recent strikes on Russian supplies and critical infrastructure in the occupied peninsula, which Ukraine ultimately wants to recapture.
There has also been a wider escalation in the Black Sea area, with Russia pulling out of a crucial grain deal and for several nights pounding the southern city of Odesa.
Videos posted on social media -- and geolocated by CNN - shows thick black smoke rising not far from a railway station in the town of Oktyabrskoye in the center of Crimea. On one of the videos, at least three loud explosions can be heard.
Sergey Aksyonov, the official installed by Russia to run Crimea, said a drone had struck an ammunition storage facility, prompting him to order the evacuation of everyone within a five-kilometer radius, and the cancellation of several train services.
There were no initial reports of casualties, he said.
It comes after Ukraine launched a drone attack on the bridge linking Crimea to Russia in the early hours of Monday, causing significant damage to part of the structure carrying road traffic.
The crossing, also known as the Kerch Bridge, is a vital supply line for Russia's war effort in Ukraine and a personal project for President Vladimir Putin.
On Wednesday, an ammunition dump was hit in the east of the territory, also causing authorities to evacuate thousands of people living nearby. Unconfirmed reports suggested that attack might have been carried out using a Western-supplied Storm Shadow missile.
Footage showed smoke and flames rolling over the site near Stary Krym in Crimea's Kirorvsky district, where blasts were heard for at six hours after the initial explosion.
And on Thursday, one person was killed when a Ukrainian drone struck four administrative buildings in the northwest of Crimea, Russian-backed authorities said.
The Ukrainian military has been carrying out sustained attacks in Crimea with the goal of harassing the Russian Black Sea fleet and disrupting vital Russian supply lines.
Reclaiming Crimea remains a goal for Ukraine and it is putting considerable effort into making Russia's occupation as uncomfortable as possible.
This week Ukrainian President Volodymyr Zelensky reiterated it was an objective, calling Crimea "our sovereign territory, an unalienable part of our nation."
He described the Kerch bridge as a target that must be neutralized, calling it an "enemy facility built outside the law, outside international laws and all applicable norms."