It started when Russia launched its full-scale invasion of its neighbour on 24 February 2022.

Russian President Vladimir Putin said his goal was to "demilitarise and denazify" Ukraine - he has repeatedly painted the country as a Nazi state. Our explainer looks at the distortions and untruths that Russia has previously spread about Nazis in Ukraine.

The Russian leader has long questioned Ukraine's right to exist, claiming that "modern Ukraine was entirely created by Russia" after the communist revolution in 1917.

In February 2022, troops moved in quickly, accompanied by dozens of missile strikes on cities across Ukraine.

Within a few weeks, Russian forces were in control of large areas of eastern, northern and southern Ukraine - and had advanced to the suburbs of the capital Kyiv.

However, they met strong Ukrainian resistance - and by November 2022 the picture had changed dramatically. Ukraine had regained ground in the north and Russia failed to take Kyiv.

Since then, progress on both sides has slowed. In recent months, Russia has been gradually expanding the amount of territory controls - particularly in the east - but gains have been minimal.

Verified material shows several smoke plumes at Yaroslavl refinerypublished at 09:01 BST

09:01 BST

By Paul Brown, Peter Mwai and Fridon Kiria

We have verified multiple videos and images shared on social media showing huge smoke plumes rising from one of Russia’s biggest oil refineries at Yaroslavl, some 280km (170 miles) north-east of the capital, Moscow.

Ukrainian media reported the facility was set ablaze following a drone attack early on Thursday.

In one of the verified images on social media there appear to be at least four fires at the site, which is about 700km (430 miles) from the border with Ukraine.

Image source, Telegram

Most of the clips appear to have been captured by people living in the city of Yaroslavl itself, several miles away from the refinery.

Image source, Telegram

Image source, EPA

Ukraine has struck two oil refineries in Russia, President Volodymyr Zelensky says.

In a social media post, he writes that Ukraine's Defence Forces struck the Slavneft-Yanos refinery in Yaroslavl and the Bashneft-Novoil refinery in Bashkortostan.

Earlier, we reported that black smoke was rising from the direction of the Yaroslavl oil refinery after Ukrainian drone attacks. Yaroslavl Governor Mikhail Evraev says the Ukrainian drones attacking the region have been destroyed, but falling debris has caused three houses to catch fire.

Zelensky says they also struck two military patrol boats and vessels from Russia's shadow fleet in the Black Sea.

We can now bring you more from Yaroslavl Governor Mikhail Evraev.

He says that while all the Ukrainian drones attacking the region have been destroyed, falling debris has caused three houses to catch fire and has shattered windows in several apartment buildings. He also describes damage to vehicles.

Information on casualties is being "clarified", he says.

Image source, Social media

Image source, State Emergency Service of Ukraine

As Ukraine launched more than 600 drones at Russia overnight, attacks continued the other way.

In the Ukrainian city of Balakliya, the state emergency service says three were killed as Russian drones attacked a residential neighbourhood.

It adds that fires broke out in homes as a result of the attacks.

Image source, Getty Images

This is not the first time energy infrastructure in Yaroslavl has been targeted by Ukrainian strikes.

"Deep strikes" were carried out on oil facilities in the region last month, according to Ukrainian President Volodymyr Zelensky in a Telegram post on 27 July.

He described the attack as part of an effort to "reduce Russia's ability to finance the war". He also describes having struck an oil facility in the region in a Telegram post on 14 June.

Meanwhile, Russia's Mikhail Evraev - governor of Yaroslavl - has described drone attacks on the region on multiple occasions in recent months, including on 6 July, 10 July, 16 July and 23 July, although his posts do not reference the refinery directly.

Image source, Reuters

The Slavneft-Yanos refinery is based in the city of Yaroslavl, hundreds of miles from the border with Ukraine.

It's one of the top five largest refineries in Russia, and was built in 1961.

It has been attacked by Ukraine before throughout the conflict.

Its website claims that it "makes about 15 million tonnes of crude oil annually", and its products include fuel for cars, jet fuel, and a wide range of oils.

It employs 3,500 people.

The Russian defence ministry says overnight, air defence forces intercepted and destroyed 605 Ukrainian drones.

This occurred over several territories, including the Moscow Region and the Black Sea, as well as Yaroslavl - home to the Slavneft-Yanos oil refinery.

Thick black smoke is rising over the Russian city of Yaroslavl this morning following a Ukrainian drone attack.

The region’s governor Mikhail Evraev says the region faced its largest-ever enemy attack, adding that they destroyed 92 drones.

Yaroslavl is home to one of the largest oil refineries in Russia and has been targeted by Ukraine in recent months.

Meanwhile, in Ukraine, three people were killed in Russian strikes on the city of Balakliya, according to officials, and 12 were injured in Sumy.

The Russian Defence Ministry says it struck two vessels transporting military goods in the port of Odesa last night.

We’ll continue to bring you updates from our teams across the region - stick with us.