According to Russian authorities, eight drones were shot down in Moscow, and there are reports that as many as 30 drones have attacked the city.
The attack has led to widespread speculation on social media about the origin of the drones. One drone caught on camera in particular baffles the experts.
"The drone in the videos is unlike any I have seen before, indicating that it may be a new system that Ukraine has developed as part of their expanding arsenal of long-range military drones," James Patton Rogers, drone expert at SDU and Cornell University, writes to SVT.
However, similarities exist with a newly developed Ukrainian drone type, which so far has not been seen to be used. So says David Hambling, journalist and author who has covered drones for many years.
"The problem is that anyone can make drones"
However, it is not possible to fully determine which drones have been used simply by analysing the videos that have been disseminated.
"If you don't get access to the wreck and can examine it, it's not easy to determine what kind of drone it is, who made it or where it came from," he says.
"The problem is that anyone can make drones nowadays. Parts are available online and for a few thousand dollars you can procure them and build a drone that is actually capable of performing this type of mission.
Even if the drones were Ukrainian, it does not necessarily mean that it is the Ukrainian government that is behind the attack. An independent pro-Ukrainian group may have carried out the attack.
According to Hambling, it is also possible, perhaps even more likely, that the drones took off from within Russia.
"It explains how they got past hundreds of kilometers of air defenses and why they weren't shot down by Russian fighter jets on their way there.