The incident took place inside the heavily fortified Black Sea Fleet base in Sevastopol on Saturday morning. The UAV (unmanned aerial vehicle) was shot down, officials in the Russian-controlled area say, and landed on the roof of a building. The resulting fire sent huge amounts of smoke into the air. Huge fireball explodes at an ammunition depot in Crimea in an earlier attack Within hours, there was heavy traffic congestion on roads outside Sevastopol, which is the largest city on the Crimean peninsula and a key port and naval base. It came a day after explosions near military bases in Russian-controlled areas of Ukraine and even Russia itself, in an apparent demonstration of Kiev’s growing ability to hit Russian assets far from the front lines. Mikhail Razvozhayev, the pro-Russian mayor of Sevastopol, wrote on his Telegram channel: “They shot down a UAV right over the fleet headquarters. He fell on the roof and caught fire… Well done guys.” There were no casualties, he said. Russian official Oleg Kryuchkov posted on Telegram that “attacks by small drones continue” in various locations around Crimea and urged citizens to remain calm. “The objective is not military but psychological,” he wrote. “The explosives are small and not capable of causing significant damage.” The headquarters of the Russian Black Sea Fleet in Sevastopol (AFP via Getty) It was not clear where the drone took off from, and the Ukrainian armed forces did not say it was behind the attack. A defense analyst said the attack appeared to have been carried out by an armed, commercially acquired drone. Earlier this week, Moscow installed a new commander of its Black Sea fleet in the wake of a series of setbacks. Late last month, another drone strike hit the same location, injuring six people, prompting Russia to beef up its defenses in Crimea. A satellite image shows the Saki air base on the Crimean peninsula after an explosion there on Wednesday (AP) Last week also saw massive explosions at an air base in Crimea. In a new assessment, a Western official said the incident had rendered half of Russia’s air force in the Black Sea useless in a single strike. This week, another explosion was reported at an airbase in Belbek, near Sevastopol. At the opposite end of the peninsula, the sky also lit up in Kerch near a huge bridge to Russia, where Moscow said it shot down a drone. Inside Russia, two villages were evacuated after explosions at an ammunition dump in Belgorod province, more than 62 miles from territory controlled by Ukrainian forces. Ukrainian authorities have not publicly claimed responsibility for attacks in Crimea or Russia, and continue to suggest they were carried out either with long-range weapons or sabotage. Non-operational Russian military equipment in Sevastopol (AFP via Getty) Ukrainian President Volodymyr Zelensky thanked US President Joe Biden for another $775 million military aid package. “We took another important step in defeating the attacker,” he tweeted. In 2014, Russia annexed Crimea, a peninsula at the top of the Black Sea and a popular holiday destination for Russians, from Ukraine.