Three military personnel have been killed following a drone attack at an air base in southern Russia, reports have stated.
The drone was reportedly shot down by air defences at the Engels airfield on Sunday evening.
"A Ukrainian unmanned aerial vehicle was shot down at low altitude while approaching the Engels military airfield in the Saratov region," news agencies reported the Russian ministry as saying.
"As a result of the fall of the wreckage of the drone, three Russian servicemen of the technical staff who were at the airfield were fatally wounded."
The Ukrainian military has not commented on the attack.
Aviation equipment at the base was not damaged, the Russian defence ministry said.
Saratov governor Roman Busargin expressed his condolences to the men’s families and friends, and said there was "absolutely no threat to residents" in the town of Engels itself.
The base lies 310 miles northeast of the border with Ukraine and comes after Russian bombs killed 13 people in Kherson on Christmas Eve, while three emergency workers died clearing landmines.
The city was attacked 41 times during the day, according to Yaroslav Yanushevich, head of Ukraine’s regional military administration.
Homes, industrial buildings, medical facilities and apartment blocks all came under fire.
Officials are now appealing for people to donate blood to victims after 68 others were injured in the bombardment of the southern city.
Posting images of streets strewn with bodies and burning cars, President Volodymyr Zelensky accused Russian troops of "killing for the sake of intimidation and pleasure".
Describing Russia as a "terrorist country", he added: "The world must see what absolute evil we are fighting against."
In a defiant Christmas address, he vowed that Ukrainians will still celebrate the festivities despite facing their 10th month of war.
The president added: "Let’s endure this winter because we know what we are fighting for."