MOSCOW (Reuters) -At least seven people were killed and 17 injured when a whole section of a Russian apartment block collapsed after it was struck by a Soviet-era missile launched by Ukraine and shot down by Russia, Russian officials said.

In one of the deadliest attacks to date on the region of Belgorod, Ukraine launched what Russian officials said was a massive missile attack with Tochka ballistic missiles and Adler and RM-70 Vampire (MLRS) multiple launch rocket systems.

Footage from the scene showed at least 10 storeys of the building collapsing. Later, as emergency services scoured the rubble for survivors, the roof collapsed and people ran for their lives, dust and rubble falling behind them.

Russia's defence ministry said the attack, which it called a "a terrorist attack on residential areas", took place at 08:40 GMT and involved at least 12 missiles.

"Fragments of one of the downed Tochka-U missiles damaged an apartment building in the city of Belgorod," the ministry said.

Russian news agencies said at least seven people had been killed and 17 injured, including two children. Others were still trapped under the rubble.

Both Ukraine and Russia say they do not target civilians, though many civilians have been killed in the war by both sides.

Russian Foreign Ministry spokeswoman Maria Zakharova said that the strike was a targeted attack on civilians which showed the criminality of both Ukraine and its backers - primarily the United States and its European allies.

There was no immediate comment from Ukraine on the attack.

KHARKIV FRONT

After heavy shelling of Ukraine's northeastern Kharkiv region, Russian forces smashed through the border over recent days and say they have pushed Ukrainian forces out of at least nine villages in the area.

The move threatens to open up a new front and has forced Ukraine to dedicate additional troops to the area just as Russian forces advance at key points along the front in the south and the east.

Russian troops on Sunday said they seized another four villages - Hatyshche, Krasne, Morokhovets, Oliinykove - in Kharkiv region in Ukraine.

Russian military bloggers said Russia was taking advantage of its numerical superiority on the battlefield to push hard into relatively undefended areas with highly mobile small units of troops, which then surrounded Ukrainian positions.

Ukraine's military chief said his country's forces were facing a difficult situation in fighting in the Kharkiv region, but that they were doing all they could to hold the line.

"Units of the Defense Forces are fighting fierce defensive battles, the attempts of the Russian invaders to break through our defenses have been stopped," Oleksandr Syrskyi said.

In response to Ukrainian attacks on Belgorod, President Vladimir Putin suggested in March that Moscow could try to establish a buffer zone inside Ukrainian territory due to the attacks on Belgorod.

Russia invaded Ukraine in February 2022.

The conflict in eastern Ukraine began in 2014 after a pro-Russian president was toppled in Ukraine's Maidan Revolution and Russia annexed Crimea, with Russian-backed separatist forces fighting Ukraine's armed forces.

About 14,000 people were killed there between 2014 and the end of 2021, according to United Nations High Commissioner for Human Rights (OHCHR), including 3,106 civilians.

(Reporting by Reuters; Editing by Sharon Singleton)

By Guy Faulconbridge