Russia has accused Ukraine of targeting President Vladimir Putin's residence at the Kremlin using drones -- an accusation Kyiv has denied.
Unverified video footage circulating on social media appears to show an explosion on the domed roof of a building known as the Kremlin Senate, which houses the presidential administration, though the exact target and perpetrator remain unknown.
Here are some key questions about the incident:
- Who carried it out? -
Moscow blamed Kyiv for attempting to assassinate Putin in a "planned terrorist act and an attempt on the life of the President of the Russian Federation."
But Ukrainian President Volodymyr Zelensky denied his country was responsible and said: "We fight on our territory, we are defending our villages and cities."
Ukrainian presidential spokesman Mikhaylo Podolyak suggested Moscow is to blame.
"Such staged reports by Russia should be considered solely as an attempt to prepare an information background for a large-scale terrorist attack on Ukraine," Podolyak said.
US Secretary of State Antony Blinken also cast doubt on the veracity of Russia's account, saying: "I would take anything coming out of the Kremlin with a very large shaker of salt."
And Eastern European expert Sergej Sumlenny said he believes Russia is responsible.
He cited factors including the Kremlin providing quick confirmation of the incident, and the circulation of apparent CCTV footage from government-controlled cameras as evidence that Russia "wants us to see it."
- Could Ukraine be responsible? -
While the perpetrator is unknown, Ukraine has the technical capabilities to carry out long-range strikes inside Russia and has done so before.
"At this point, it may be Ukraine's own UJ-22 drone, or a Chinese-made Mugin-5, which was apparently used by Ukraine before," while Kyiv's PD-1 drone is another option, said Samuel Bendett, a researcher in uncrewed military systems who is an analyst with the CNA Russia Studies Program.
The UJ-22 "has a long range and can potentially reach Moscow," but it is unclear where the drones were launched from at this point, said Bendett, who emphasized that much is still unknown as of now.
Dominika Kunertova, senior researcher at the Center for Security Studies at ETH Zurich, agreed.
"I think it's possible that Ukraine has developed a long-range drone capability that could reach Moscow. Extending the strike distance has been Ukraine's main objective regarding innovation in uncrewed systems," Kunertova said.
But she added that "one of the main strategic advantage of using a drone for this purpose is deniability" -- the more difficult it is to trace any attack back to Ukraine, the less chance of any escalation in the conflict.
- What impact will it have? -
In terms of physical damage, very little: AFP saw some people climbing external stairs onto the Kremlin Senate roof, which appeared to be unscathed.
People were also out strolling in the area, and there was no strengthened police presence there.
But a strike by an adversary on the heart of the Russian government would still carry "a strong psychological impact," Bendett said.
It would also raise questions about the quality of Russian air defenses.
"Russian commentators hinted even last year it probably can't protect the entire country and that there may be gaps that can be exploited," Bendett said, though it is "unclear why this drone was not intercepted over Moscow."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
