After a family of four was killed by Russian artillery shelling of the southern Ukrainian region of Kherson, President Volodymyr Zelensky has announced retaliation.

“Every occupier destroyed, every piece of Russian equipment burned, fire instead of their headquarters and warehouses, the very eloquent smoke on Kerch bridge and more – all this proves that we will not leave any of Russia’s crimes unanswered,” he said in his Telegram video on Sunday.

In the Kherson region alone, authorities say seven people were killed and about 15 others injured.

In the village of Shyroka Balka, Russian artillery killed five people – including a family of four – father, mother, a 12-year-old son, and a baby girl only about three weeks old – on Sunday morning, according to Ukrainian authorities.

The region was shelled 17 times by Russian army fire during the day, Zelensky said in his address.

The local military administration announced a regional day of mourning in the region on Monday.

The baby girl’s parents were also killed in the village of Shyroka Balka, Interior Minister Ihor Klymenko said on Telegram.

The baby’s 12-year-old brother was taken to hospital with life-threatening injuries, Klymenko said.

He later died in hospital.

In the neighbouring village of Stanislav, two adults were killed, according to the head of Ukraine’s presidential office, Andrii Yermak. “The enemy continues to shell the Kherson area,” he said.

The villages are located on the western bank of the Dnipro River at its mouth into the Black Sea.

Russian troops withdrew from the area last autumn.

However, it is still within the range of their artillery.

At least 500 children have been killed so far in the Russian invasion of Ukraine, launched by Moscow more than 17 months ago, Ukrainian prosecutors said on Sunday.

Another 1,100 children suffered injuries of varying degrees, the prosecutor’s office in Kiev said, adding that the actual number is likely to be higher as the authorities continue to investigate casualties in the war zone and in areas liberated by Ukraine, as well as in regions occupied by Russian troops.

The number of children killed and injured was highest in the eastern regions of Donetsk and Kharkiv near the frontline, followed by the capital region of Kiev and Kherson in southern Ukraine.

Russia has been waging an all-out war against neighbouring Ukraine for more than 17 months.

During this time, Russian troops have repeatedly shelled civilian objects, cities and towns.

The United Nations has officially registered more than 9,000 civilians killed in the conflict, but the actual number is probably much higher.

Across the border in Russia, meanwhile, the military on Sunday said it had shot down a total of four drones over the south-western regions of Kursk and Belgorod bordering Ukraine.

There was no damage or casualties, the Defence Ministry in Moscow said without providing further details.

The information could not be independently verified.

Three of the drones were intercepted over the Belgorod region, one of them overnight, according to the ministry.

In recent weeks, Russia has repeatedly reported what it says are Ukrainian combat drones causing damage as far as in the capital Moscow.

Russian minefields are a serious obstacle for Ukrainian troops, according to Defence Minister Oleksii Reznikov.

In an interview with Britain’s Guardian newspaper published on Sunday, he spoke of minefields hundreds of kilometres wide and millions of explosive devices along the front line.

According to Reznikov, there are up to five mines per square metre in some parts of the front line.

According to the Guardian, Reznikov is convinced that the huge minefields could be crossed.

However, the defence minister stressed that it was crucial that allies expand and accelerate the training of Ukrainian deminers already offered by some nations.

On Saturday, Ukrainian President Volodymyr Zelensky already stressed the importance of international assistance in mine clearance.

Due to mines and unexploded ordnance, around 174,000 square kilometres of Ukrainian territory is currently said to be dangerous to people.

These figures cannot be independently verified at present.

Ukraine has been defending itself against Russia’s full-scale invasion for more than 17 months.

In the current counteroffensive, the Ukrainians are encountering minefields, anti-tank trenches and other obstacles, as well as staggered Russian defence lines.