Russia launched a full-scale invasion of Ukraine in the early hours of Thursday morning, with shelling and rocket attacks on several major cities leaving scores dead and hundreds injured.
Vladimir Putin’s assault saw Russian troops enter Ukraine from the north, east and south of the country, bombarding airports and even taking the Chernobyl nuclear power plant.
Shelling and missile strikes have been reported all over the country, with experts saying the airstrikes are being used to clear the way for ground forces to move in.
So, what is the current situation in Ukraine’s various cities and regions? And what are surrounding European countries doing?
Here is everything you need to know.
Within Ukraine (clockwise on map)
Kyiv
Having crossed the border and headed for the capital, which sits in the north of Ukraine, Russian troops took control of one of Kyiv’s airports, Antonov International, after launching a large air assault operation.
The airport, which is geographically significant because it is 15 minutes from the capital, is Ukraine's most important international cargo airport and a key military airbase.
Images showing long queues of traffic were circulated on news outlets and social media, and were said to be an attempted mass exodus by panicked Kyiv residents.
Ukraine’s Korrespondent news outlet reported at around 6am local time (4am GMT) that traffic jams had formed from central Kyiv towards Zhytomyr and other exit routes.
Local authorities have been urging Kyiv residents to stay at home, though.
US officials warned on Thursday evening that Kyiv could fall within hours, with concerns that Putin’s goal is to remove the government and install a puppet regime.
Kharkiv
Residents living in the northeastern city of Chuguiv, in Kharkiv, told local media they had woken to the sound of bombing.
Eventually, a missile attack left a crater around 4 metres wide in the ground between two five-floor residential buildings in one residential district.
It was among the first reported damage after Russia launched its invasion and left several other buildings on the street badly damaged, with windows shattered and doorframes hanging off.
Dnipro
An explosion in Dnipro, a city in central Ukraine, was filmed early on Thursday. Watch the footage below.
Mariupol
The port city of Mariupol was attacked overnight, with mayor Vadym Bouchenko announcing that three people had been killed and six others, including a child, injured due to Russian shelling in one of its suburbs.
Russians also attacked the airport and a village nearby, he added.
“Don’t panic,” Mr Bouchenko said. “We are ready to fight for Mariupol and Ukraine.”
Odessa
In the southern city of Odessa, 18 people were killed as a result of a missile attack on a military base near Ukraine’s Black Sea port, regional authorities said.
“Eighteen died – eight men and 10 women. At the moment, we are still digging through the rubble,” the Odessa regional administration reported in a statement.
Both Mariupol and Odesa are home to Ukraine naval bases, so it was no surprise they came under heavy attacks.
Crimea
CCTV footage of Russian troops crossing the border from Crimea into Ukraine was some of the first to be seen after President Putin announced his military operation.
Crimea, a peninsula at the top of the Black Sea, was annexed by Putin in 2014 in part of a wider conflict between pro-Russian separatists and Ukrainian forces.
Prior to the annexation, Ukraine and the West had become worried about the Russian troops’ concentration in the east of the country and urged Moscow to pull them back.
But Russia argued that it was free to deploy its forces on its territory and sternly warned the government in Kyiv against using force to reclaim control of the rebel-held territory east where more than 14,000 people have died in seven years of fighting.
The United States and the European Union imposed sanctions on Moscow for its annexation of Crimea, which isn’t recognized by most of the world.
Russia sees Crimea as a geo-strategically important area and has a naval base there.
Donetsk and Luhansk
The two separatist regions in the country’s east were taken by Russia on Monday, prompting the UK, EU and US to impose their first set of sanctions on Moscow for what they said was a “renewed invasion” of Ukraine.
After President Putin declared the areas would be officially recognised as independent by Russia, he ordered military troops to move in.
As the map shows, Russian troops used these now-claimed regions to cross into Ukraine as part of their assault.
The self-proclaimed Donetsk People’s Republic (DPR) and the Luhansk People’s Republic (LPR) declared their independence in May 2014 after Crimea was annexed.
The DPR and LPR are officially considered terrorist organisations by Kyiv , although that is not a designation agreed upon by the US, EU or other international bodies.
Chernobyl
Ukraine has said Russian troops have seized the Chernobyl plant – in the country’s northwest – after fierce fighting on Thursday.
“Russian occupying forces are trying to take over the Chernobyl Nuclear Power Planty,” President Volodymyr Zelensky wrote on Twitter beforehand.
“Our soldiers are giving their lives so that the tragedy of 1986 does not happen again,”
The decision to target the site of the nuclear disaster marked “a declaration of war on all of Europe,” Mr Zelensky added.
Shortly after 5pm, it was confirmed President Putin’s military had seized the plant.
The Chernobyl exclusion zone, which is on the border with Belarus, offers a short, direct route to Kyiv .
Neighbouring countries
Belarus
Belarusian president Alexander Lukashenko said his troops could take part in Russia’s military operation against Ukraine if needed, and that he would discuss strengthening the country’s western flank with Putin.
Border guard CCTV footage captured Russian forces crossing into Ukraine via the Senkivka-Veselivka border checkpoint with Belarus.
The nation has become a servant of Moscow under its strongman leader, with the Nato military alliance estimating there were 30,000 Russian troops on Belarusian soil prior to the invasion.
Putin spoke to Lukashenko shortly after the Russian assault began, according to state media Belta.
“He [Putin] gave me a detailed introduction to the situation and most importantly, to the development of the situation,” Lukashenko was quoted as saying in a meeting with the Belarusian military.
Lukashenko stressed Belarusian troops did not participate in the Russian invasion, but that they could take part “if necessary”.
Boris Johnson announced earlier that some of the financial sanctions placed on Russia by the UK would be extended to Belarus for its role in aiding the assault.
Poland
Ukrainians fleeing the Russian invasion started trickling into Poland this afternoon, with dozens arriving at the Medyka crossing – some carrying luggage and accompanied by children.
Officials in EU countries bordering Ukraine, including Romania and Slovakia, reported there was no big influx of refugees for now, but local media and witnesses said foot traffic was increasing as the day went on.
Prime minister Mateusz Morawiecki told Poland earlier that “innocent people are being killed” in Ukraine, and appealed to the nation to extend every possible assistance to those who have “found themselves in need of help”.
