The ongoing Ukrainian incursion into Russia's Kursk region appears to be an unprecedented offensive aimed, experts say, at diverting Russian resources from other regions or undermining morale in Russia.
• Read also: Ukrainian Incursion: ‘Russian Propaganda’ Targeted by Drone Strike in Russia’s Kursk Region
• Read also: 'Military aviation strikes inflict damage on the enemy': Fighting in Russia's Kursk border region
• Read also: Ukrainian incursion into Russia: 'several thousand' people evacuated
In Kiev, the authorities are unusually silent: no one officially acknowledges the existence of this operation, and senior officials refuse to comment, even on condition of anonymity.
For its part, Moscow is content to publish rare information, seeking to balance between condemning this escalation and the desire to avoid panic.
As the fighting enters its third day, here are the key questions surrounding this cross-border incursion:
What happened?
Ukrainian forces launched an offensive in the Kursk region of southwestern Russia at around 8 a.m. Moscow time (6 a.m. GMT) on Tuesday morning, according to the Russian military.
Ukraine has committed to sending 1,000 troops and several dozen tanks and other armored vehicles, according to Russia.
The latter accused Ukrainian forces of indiscriminately striking civilian buildings and sent reinforcements backed by fighter jets and artillery to repel the attack in the area, where a state of emergency was declared.
At least five civilians have been killed there and 31 wounded since the incursion began, Russian officials said on Wednesday.
Several thousand people have fled the fighting zone on the Russian side, while Ukraine has ordered the evacuation of about 6,000 people in the Sumy region on the other side of the border.
Is such an incursion common?
The current offensive appears unusual because of its supposed scope and because it appears to involve regular Ukrainian forces.
Ukrainian fighters have previously made several short incursions into Russia, which were claimed by units claiming to be made up of Russians fighting alongside Ukraine, namely the Russian Volunteer Corps and the Russian Freedom Corps.
Thus, in mid-March, during the Russian elections, Ukrainian attack groups repeatedly tried to seize territory in the neighboring Belgorod region, officials say.
Ukraine's allies appeared to be caught off guard by Tuesday's attack, and Washington said it had contacted Kyiv for more information.
“The images showing the destruction of Russian and Ukrainian equipment, helicopters, the use of aviation and the use of artillery on both sides” were signs of a large-scale military operation, Kiev-based military analyst Sergei Zgurets told AFP.
How far have Ukrainian forces advanced?
The Institute for the Study of War (ISW) announced on Thursday that Ukrainian forces have advanced up to ten kilometers into Russian territory.
The campaign focused on the logistics center in Sudja, a town of 5,500 people located eight kilometers from the Ukrainian border.
Russian military bloggers with ties to the military also reported significant advances, with some saying Ukrainian forces had taken partial control of Sudzha and the villages.
What are the goals?
The objectives of this operation are not yet clear, and in the absence of official Ukrainian comments, experts are putting forward several hypotheses.
For some, the incursion could draw Russian reserves away from Ukraine's Kharkiv region (northeast of the country), where Russia launched an offensive in May.
“At the moment, this is a limited operation, the direct result of which will be the destabilization of the Russian group attacking Kharkiv or lurking around it,” military analyst Oleksiy Kopytko said on social networks.
“Judging by the scale and intensity of the Ukrainian operation, sooner or later the enemy will be forced to withdraw its forces from other theaters of operations,” Kostyantyn Mashovets wrote on Facebook.
The attack could also have a psychological effect, boosting the morale of Ukrainians who see their military struggling elsewhere, while destabilizing Russia.
“Another goal is to show Russian society what it feels like when your territory is occupied,” Sergei Solodky, a senior official at the New Europe think tank in Kiev, told AFP.
Finally, some say that if Ukraine is able to hold onto these territories, it could make them a card to play against Russia in the context of hypothetical peace negotiations.
It is crucial for Ukraine to put all its assets on its side ahead of the US presidential election that could once again install a skeptical Donald Trump in the White House.