Ukrainian law enforcement officers work at the site of a missile attack in Lviv on Wednesday. AFP

A Russian strike on the historic centre of Lviv in western Ukraine has killed seven people including three children, officials said on Wednesday, a day after a particularly bloody attack in the central city of Poltava in which dozens died.

Moscow has stepped up its aerial attacks after Ukraine's offensive in Russia's Kursk region, which caught Russian troops by surprise.

The overnight attacks triggered renewed calls from Ukrainian officials for Western partners to provide air defence, as well as long-range weapons to retaliate by striking targets deep inside Russia.

"In total, seven people died in Lviv, including three children," Internal Affairs Minister Igor Klymenko wrote on Telegram, upping the previously reported toll.

He said search and rescue operations were still going on in Lviv, a western city near the Polish border that has largely been spared over the last two and a half years of war.

Sirens rang out over Lviv before sunrise on Wednesday, according to Mayor Andriy Sadovy, who advised people to take shelter as air defences worked to down a barrage of missiles.

Ukrainian rescuers load the body of a killed person following a missile attack in Lviv on Wednesday. AFP

The missile attack wounded 40 people, the prosecutor's office said, damaging schools and medical facilities as well as buildings in the city's historic centre.

‘Inhuman screams’

"I heard terrible inhuman screams saying 'Save us'," said Yelyzaveta, a 27-year-old resident of Lviv who rushed to shelter in her basement.

Others like Anastasia Grynko, an internally displaced person from Dnipro, did not have time to reach a shelter.

"The rocket hit our house. Everything was blown away. At the time of the explosion, I was somehow miraculously in the corridor, so I was not badly hurt," she said.

President Volodymyr Zelensky denounced what he called "Russian terrorist strikes on Ukrainian cities".

Lviv region head Maksym Kozytsky said that "at least seven architectural objects of local importance were damaged", adding that "all the buildings are located in the historical area and in the UNESCO buffer zone."

The attack in Lviv was part of a wider barrage on Ukraine, with 13 missiles and 29 drones launched over the war-torn country, the air force said.

The air force said it downed seven missiles and 22 drones.

Agence France-Presse