Denis Pushilin described the strike on a busy market as "horrendous", and said the number of casualties could rise.

A Ukrainian army group operating in the region said it did not carry out the attack. Mr Pushilin blamed Ukraine.

BBC News was not able to immediately verify the circumstances around the strike.

Photographs published by Reuters news agency appeared to show destroyed shop fronts, as well as bodies lying in the street.

According to AFP, a local resident named Tatiana told local media she heard an incoming projectile overhead, and hid under her market stall.

"I saw smoke, people screamed, a woman was crying," she was quoted as saying.

In a statement posted on Facebook, the Tavria unit - part of the Ukrainian army - said its forces "did not engage in combat operations in this case".

It continued: "Donetsk is Ukraine! Russia will have to be held accountable for the lives of Ukrainians taken."

The Russian Foreign Ministry called it "a barbaric terrorist act against the peaceful people of Russia" by Ukrainian forces who, it said, had "used weapons supplied by the West".

Donetsk city and parts of the wider region in eastern Ukraine were first seized by Russian-backed forces in 2014, and the area has been partially controlled by Moscow ever since.

The city is around 20km (12 miles) from the frontline. Areas near Donetsk city - including Mariinka and Avdiivka - have seen some of the fiercest fighting of late.

It has been almost two years since Russia launched its full-scale invasion of Ukraine, but it has made little progress in recent months.

On Saturday it claimed to have captured the village of Krokhmalne in north-eastern Ukraine's Kharkiv region. A Ukrainian military spokesman confirmed its forces had withdrawn from the area, but said the territory was of little military importance.

Days earlier Moscow also claimed to have taken control of a settlement named Vesele in Donetsk. Kyiv has not confirmed the claim.

By Oliver Slow