Russia carried out artillery and air strikes in the Zaporizhzhia region, Ukraine's General Staff said on Tuesday, where fighting near Europe's largest nuclear power plant has raised fears of a catastrophic nuclear incident.

The attacks come ahead of Ukraine's Independence Day on Wednesday commemorating freedom from Soviet rule, with Kyiv banning public celebrations citing a threat of more attacks.

The U.S. embassy in Kyiv also warned in a statement of Russian plans to strike civilian and government infrastructure in the coming days.

Near frontlines in the south of the country, Ukraine said Russia fired artillery and conducted air strikes in several towns in the Zaporizhzhia region, were Russian forces captured the nuclear power plant shortly after they invaded on Feb. 24.

Artillery and rocket fire near the Zaporizhzhia nuclear reactor complex, on the south bank of the Dnipro River, has led to calls for the area to be demilitarised.

Ukrainians living nearby voiced fears shells could hit one of the plant's six reactors, with disastrous consequences.

"Of course, we are worried. ... It's like sitting on a powder keg," Alexander Lifirenko, a resident of the nearby town of Enerhodar, said on Monday.

Ukrainian President Volodymyr Zelenskiy has warned that Moscow could try "something particularly ugly" in the run-up to Wednesday's 31st independence anniversary, which also marks half a year since Russia invaded.

Fearing renewed rocket attacks, authorities in Kyiv moved to ban public events related to the independence anniversary from Monday until Thursday. The capital is far from the front lines and has only rarely been hit by Russian missiles since Ukraine repelled a ground offensive to seize the capital in March.

In Kharkiv, a northeastern city that has come under frequent and deadly longer-range artillery and rocket fire, Mayor Ihor Terekhov announced an extension to an overnight curfew to run from 4 p.m. to 7 a.m. effective from Tuesday to Thursday.

Fears of attacks have mounted after Russia's Federal Security Service on Monday accused Ukrainian agents of killing Darya Dugina, daughter of a Russian ultra-nationalist ideologue, in a car bomb attack near Moscow that President Vladimir Putin called "evil". Ukraine denies involvement.

The two sides have traded blame over frequent shelling at the Zaporizhzhia nuclear plant, where Kyiv accuses Moscow of basing troops and storing military hardware. Russia denies this and accuses Ukraine of targeting Zaporizhzhia with drones.

Moscow requested a U.N. Security Council meeting be held on Tuesday to discuss the Zaporizhzhia plant, Russian state-owned news agency RIA reported, citing Deputy Ambassador to the U.N. Dmitry Polyanskiy.

CIVILIAN TOLL

Russia launched on Feb. 24 what it calls a "special military operation" to demilitarise its smaller neighbour and protect Russian-speaking communities. Ukraine and its Western backers accuse Moscow of waging an imperial-style war of conquest.

The Office of the U.N. High Commissioner for Human Rights, citing its monitoring mission in Ukraine, said on Monday 5,587 civilians had been killed and 7,890 wounded between Feb. 24 and Aug. 21, mainly from artillery, rocket and missile attacks.

UNICEF, the U.N. children's agency, said at least 972 children have been killed or injured over six months of war.

"The use of explosive weapons has caused most of the child casualties. These weapons do not discriminate between civilian and combatant, especially when used in populated areas as has been the case in Ukraine," the agency's executive director, Catherine Russell, said in a statement.

Separately, General Valeriy Zaluzhnyi - Ukraine's army chief - provided what appeared to be the first public Ukrainian military death toll, saying nearly 9,000 soldiers had died in action.

Russia has not said how many of its soldiers have been killed. Ukraine's General Staff have estimated the Russian military death toll at 45,400.

Reuters has been unable to verify military losses.