At least eight people have been killed in an attack on a residential area in the eastern Donetsk region of Ukraine, the country's authorities have said.

Ukraine's interior ministry said another 13 people were wounded in the Russian shelling of the town of Lyman.

The strike caused fires in a house, a printing shop and three cars which have now been put out by rescuers, the ministry said.

It comes as the country marks the 500th day of the invasion.

Ukraine's counter-offensive, which began last month, continues to grind on in the eastern Donetsk and south-eastern Zaporizhzhia regions.

Its advances have been slow, as Russia continues its missile and drone attacks.

The small city of Lyman is a key railway hub in the Donetsk, and was initially captured by Russia but then retaken by Ukraine's army in October.

Russia had been "concentrating quite powerful forces" there, the spokesman of Ukraine's eastern group of forces, Serhiy Cherevatyy, told Ukrainian television on Friday.

"At around 10:00, the Russians struck the town with multiple rocket launchers," the regional governor of Donetsk, Pavlo Kyrylenko, said on social media on Saturday. He said a house and a shop were damaged.

The BBC has not been able to verify the claims.

On Thursday, 10 people, including a woman aged 95, were killed after a Russian rocket hit an apartment building in Lviv, western Ukraine.

Another 40 people were injured in what the mayor of Lviv described as "one of the biggest attacks" on the city's civilian infrastructure.

And the previous week 13 people were killed - including children - when a restaurant and shopping centre were struck in Kramatorsk, an eastern city close to Russian-occupied parts of Ukraine.

For months, Russia has been carrying out deadly missile and drone attacks on Ukrainian cities, often hitting civilian targets and causing widespread blackouts.

On Saturday, Ukrainian President Volodymyr Zelensky visited Snake Island - a place that has became a symbol of Ukrainian resistance after being retaken by Ukrainian forces - to mark the 500th day of the invasion.

"I want to thank from here, from this place of victory, each of our soldiers for these 500 days," Mr Zelensky said.

One month into its long-awaited counter-offensive, Ukraine says its forces are making gains - although Mr Zelensky previously admitted progress was slow.

And earlier this week, the US's highest-ranking military officer, Gen Mark Milley, said although Ukraine was advancing steadily, its counter-offensive against Russia would be difficult and "very bloody".

The Ukrainian General Staff has reported that Ukrainian forces have conducted offensive operations south and north of what is left of the eastern city of Bakhmut - most of which has been under Russian control.

Last week, Ukraine's military commander-in-chief said its campaign had been hampered by a lack of adequate firepower and expressed frustration with the slow deliveries of weapons promised by the West.

But on Friday, the US announced it would be giving Ukraine cluster bombs - a controversial type of weapon that is banned in more than 120 countries, including the UK, because they have a record of killing civilians.

The US has faced criticism for its decision, but Mr Zelensky thanked the US for the "timely, broad and much-needed" aid.