Russia has blamed Ukraine for what it called an assassination attempt on President Vladimir Putin, referring to an incident in which two drones appeared to strike the roof of the Kremlin early on Wednesday morning, Moscow time.
Ukraine's government, however, has flatly denied any involvement, declaring it knows nothing about the incident and announcing air alerts in Kyiv and other parts of the country in anticipation of possible retaliatory strikes.
Some experts, such as John Spencer, the chair of urban warfare at West Point's Modern War Institute, are pointing to the incident as a possible false flag operation, meaning Russia may itself have staged the attack in order to justify a significant increase in hostilities as part of its ongoing invasion of Ukraine.
"Think twice about this. 1) Russia lies more than truth 2) Russia needs such an attack to justify continuing their illegal war in Ukraine 3) Ukraine not that stupid, no military target in Kremlin 4) Plenty want Putin dead," Spencer tweeted.
Others, such as Michael Horowitz, Le Beck International's head of intelligence, say it is conceivable that the drone strike was a real attack, although it is unlikely to have been an assassination attempt as the Kremlin has portrayed it.
Shashank Joshi, defence editor for UK-based current affairs newspaper The Economist, told the ABC he is keeping an open mind.
"The Kremlin has a long history of staging such incidents in order to justify the war or justify some provocation," he said.
"We've seen this going back to the very early years of Vladimir Putin's time in office, and we saw this at the beginning of this war as well. So I emphasise it could be a Kremlin provocation.
"However, having said that, I've just got back from Kyiv a couple of days ago, I spent a week there, and it was absolutely clear to me that Ukrainian officials have been putting enormous effort into long-range strike drones.
"I absolutely don't rule out that this is a bold, incredibly impressive in some ways, attack on the centre of Russian decision-making."
What evidence might point to a false flag operation?
While it's impossible to know for sure, several factors could point to this incident being not entirely what it seems.
While Ukrainian forces, or at least pro-Ukrainian saboteurs, have launched some attacks on Russian territory since the beginning of Russia's invasion, they have been largely concentrated in the regions of Russia bordering Ukraine, and have mostly been limited to strategic targets.
Kyiv has established a pattern of behaviour when it comes to acknowledging these incidents, declining to accept direct responsibility but heavily implying that Ukraine is behind them, or at least supports them and believes they are a justified consequence of Russia's invasion.
In this case, the denial from Kyiv has been categorical, with senior officials and President Volodymyr Zelenskyy explicitly stating Ukraine wasn't involved in the incident at the Kremlin and denying any knowledge of it.
A direct attack on the Kremlin, a heavily fortified complex in the centre of Moscow that serves as the seat of Russia's presidential power, would without doubt be Ukraine's most audacious strike yet, but for little strategic gain and with the likelihood of provoking a much greater Russian response.
An adviser to Mr Zelenskyy, Mykhailo Podolyak, said as much in the attack's aftermath.
"We do not attack the Kremlin because, first of all, it does not solve any military problems. Absolutely. And this is extremely disadvantageous from the point of view of preparing our offensive measures," he said.
"And most importantly, it would allow Russia to justify massive strikes on Ukrainian cities, on the civilian population, on infrastructure facilities. Why do we need this?"
The timing of the attack, which occurred in the early hours of the morning and inflicted no casualties — not to mention that Mr Putin wasn't in the building — could also point to an attempt to stage a visually striking incident that would inflict no real lasting damage.
On the other hand, a visually striking incident in the heart of Moscow might be exactly the kind of public relations victory a country like Ukraine could be hoping to achieve — especially at this time of year.
Why would an attack on Russia be significant now?
The incident at the Kremlin took place in the lead-up to Victory Day, which will be officially celebrated on Tuesday, May 9.
Victory Day is a highly significant day on the Russian national calendar, commemorating the Soviet Union's triumph over Nazi Germany in World War II.
There were fears last year that Mr Putin would use the military-themed holiday to significantly bolster support for his invasion of Ukraine, although Russia's limited success on the battlefield at that point meant celebrations were muted.
Maintaining public support for the fledgling war is crucial for Mr Putin, as a long-promised Ukraine counter-offensive looks to sap Russian resources and inflict even greater casualties than what are already being suggested Russia has suffered.
Those casualties include reports of Russian tanks streaming over bodies of dead Russian soldiers in battlefields across Ukraine.
The Economist's Joshi says the Russian president is desperate for a military victory in the lead-up to Victory Day.
"Last year we saw the parade was dramatically scaled down because of the war, and indeed Russia hoped to capture the port city of Mariupol last year. Mariupol held out for another week, effectively depriving Putin of that achievement," he said.
"Again, this time around we see that Russia's army is desperate to capture the town of Bakhmut in eastern Ukraine by May 9, in order to claim some type of victory."
Australian Strategic Policy Institute senior analyst Malcolm Davis says regardless of the nature of the drone attack itself, what matters now is how Mr Putin exploits it to retaliate against Ukraine and to further suppress opposition inside Russia.
