It's almost two weeks since Ukraine became the first foreign nation since the Second World War to occupy Russian soil.
Its surprise incursion in to Russian territory in the western region of Kursk on August 6 has been a twist in the war which had been, predominately, at stalemate for months.
Ukraine's infiltration into Russia will be seen as an embarrassment for Russian President Vladimir Putin and already the Kremlin has vowed to retaliate with a "worthy response" following the "major provocation".
The assauIt comes two and a half years after Russia launched a full-scale invasion of its smaller neighbour.
The clock is now ticking for Russia to respond, Keir Giles, senior consulting fellow on the Russia and Eurasia programme at the Chatham House think tank, told The National
"Ukraine’s incursion is impressive but we should still remember the extent of Russian territory taken and the duration of this event," he said. "We should be used to surprises from Ukraine and for each surprise it starts a new phase in the war that is different from before.
"Ukraine is still considering its operation and how to exploit the gains made but it might depend on whether Russia succeeds in getting its act together in making an effective counter offensive for what Ukraine is holding.
"Ukraine's commanders will be alert to the danger of overstretching and cautious of Russia’s potential tactics of delays for time to build up the forces required for a counter offensive.
"However there is no doubt the clock is ticking for Russia, as this is not a situation the Kremlin will be wanting to be seen as out of control for very much longer."
Kyiv's daring attempt to change the dynamics of the conflict has provided the nation with a much-needed morale boost as Russia begins to intensify its push to try and take the south-eastern city of Pokrovsk, one of Ukraine's main defensive strongholds and a key logistics hub in the Donetsk region.
Dr Matthew Ford, senior lecturer in international relations at University of Sussex, told The National the incursion will have boosted morale, even if it is not necessarily a significant military victory.
"It has been just under two weeks now, they have gone 20km into Russia and captured lots of prisoners," he said.
"Clearly the troops will have been given a morale boost and that will have been successful. But there are lots of other things going on in the background. This was not an operation to encircle large numbers of Russian units, they have taken undefended territory.
"They have taken prisoners of war but have they destroyed fighting Russians? Not likely.
"Russia is still advancing in the south of Ukraine and it knows Ukraine doesn’t have the military power to get into Moscow. Russia's strategy has been strength and thinning Ukraine’s lines and Ukraine is playing into that strategy. It doesn’t have enough infantry.
"But it will have been good for morale. This operation makes it look like they are doing something."
On Friday, Ukrainian military authorities in Pokrovsk urged civilians to speed up their evacuation because the Russian Army is quickly closing in.
Pokrovsk officials said in a post on the Telegram messaging app that Russian troops are “advancing at a fast pace. With every passing day there is less and less time to collect personal belongings and leave for safer regions.”
Ukrainian President Volodymyr Zelenskyy warned that Pokrovsk and other nearby towns in the Donetsk region were "facing the most intense Russian assaults".
"Militarily, Russia does not care about the advance into Kursk, as it is continuing to advance into Ukraine’s territory," Dr Ford said.
"Kursk is a nine-hour drive from Moscow and it would take several weeks to get to the other side of Russia. Ukraine doesn’t have the military power to take Russia, they hope Russia will collapse, or give up or topple Putin or Russian morale will collapse. I do not think this is very likely."
Ukraine is wagering it can cope with the strain on its resources involved in the attack in Kursk without sacrificing Donetsk but Russia apparently appears confident it can contain the incursion without needing to ease up in Donetsk.
“Both cannot be right,” said Nigel Gould-Davies, a senior fellow at the International Institute for Strategic Studies think tank. “The outcome hangs in the balance.”
Russia’s slow slog across Donetsk this year has been costly in terms of troops and armour, but its gains have mounted.
On Friday, White House national security spokesman John Kirby said the US will announce more security assistance for Ukraine in the coming days.
"Ukraine has once again silenced many of their critics who said its position is hopeless and exhausted on land but probably the most desired effect is on the US as Ukraine has once again conclusively shown it is capable of embarrassing Russia," Mr Giles told The National.
Ukraine's Interior Minister Ihor Klymenko said Ukrainian forces have now set up storage facilities in its northern region of Sumy to send humanitarian aid to Russian civilians across the border in Russia's Kursk region.
"The citizens abandoned by Russia are mostly elderly people, people with disabilities, and families with children. They need food, water and medicine," he said on Telegram.
Ukrainian officials said they plan to create evacuation corridors from the Kursk region and to open access to international humanitarian missions.
