From the industrial heartland of Donbas to Crimea on the Black Sea, Russia has annexed all, or part, of five regions of Ukraine, after "referendums" rejected by the international community.
Here are some key facts about the Russian-occupied regions, which currently make up an estimated 19.4 percent of Ukraine's territory, according to the US-based Institute for the Study of War (ISW). Nearly 12 percent has been taken since Moscow invaded its ex-Soviet neighbour on February 24.
Together they form a continuous swathe of territory linking southwestern Russia to the warm water ports of the Black Sea.
- Lugansk -
The Lugansk region, home to 2.1 million people before the war, borders Russia on three sides and forms part of the industrial Donbas area along with neighbouring Donetsk.
According to the ISW, over 99 percent of the territory is currently under Russian control.
Until Russia's invasion in February, Moscow-backed separatists had controlled just under half of the region since 2014, when nationwide demonstrations ousted Ukraine's Kremlin-friendly president.
After a battle of attrition that lasted months, Russia pushed Ukrainian forces out of Lugansk altogether in early July this year, a move trumpeted by Moscow as a strategic victory.
But Kyiv's successful advances in September have seen Ukrainian forces edge back into the region.
- Donetsk -
Donetsk, which had a pre-war population of 4.1 million, is a mining and steel base in the larger Donbas area, and is home to one of Ukraine's largest cities, also named Donetsk.
Before February 24, around half of the prominently Russian-speaking region was controlled by Moscow-backed separatists.
Today, around 58 percent is controlled by Moscow and its allies, including the port city of Mariupol, which was reduced to rubble during a brutal siege.
Fighting has raged for months around a frontline in the centre of the region.
- Zaporizhzhia -
The Zaporizhzhia region, which is home to Europe's largest nuclear plant on the Dnipro river and had a pre-war population of about 1.6 million, borders the Sea of Azov.
According to the ISW, 72 percent of the land is currently assessed to be under Russian control.
The region's main city of Zaporizhzhia remains in Ukrainian hands, although Moscow controls its main port, Berdyansk.
Russian troops seized the nuclear facility in March and fighting near it in recent weeks spurred calls from Kyiv and its allies for the establishment of a demilitarised zone around it.
- Kherson -
The westernmost of the four regions that held annexation "referedums" is Kherson, which was one of the first Ukrainian regions to fall under Russian control after the invasion began.
With a population of one million before the war, this key agricultural area forms the gateway to the Crimean peninsula.
Ukraine's counterattack in Kherson in August triggered the relocation of Russian reinforcements -- which cleared the path for a successful assault by Kyiv in the eastern Kharkiv region.
Partisans have reportedly attacked Russian occupation units and officials, while Ukrainian forces have destroyed river bridges leaving Russian units at risk of entrapment.
Over 80 percent of the region is estimated to be under Russian control.
- Crimea -
Crimea, the Black Sea peninsula seized by Russia from Ukraine in 2014 after a "referendum" deemed illegal by Ukraine and the West, is a picturesque region of vineyards and tourist resorts -- and a historic hotbed of geopolitical tensions.
Russia's Black Sea fleet has long been based at the Crimean port of Sevastopol.
Soviet leader Nikita Khrushchev gave Crimea in 1954 as a "gift" to Ukraine, but this was a largely symbolic move as both Ukraine and Russia were parts of the same country.
When the Soviet Union collapsed in 1991, Crimea became part of independent Ukraine.
The seizure of the peninsula of mostly Russian speakers was popular among Russians, stoking nationalist sentiment.
In May 2018, Russian President Vladimir Putin opened a 19-kilometre-long bridge, connecting it to the Russian mainland.
Russia has used Crimea as a base to attack Ukraine since February but the peninsula itself was largely spared attack until August, when Russian military bases there were hit by missiles.
Ukraine later admitted it had targeted the territory.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
