A resident of the eastern Ukrainian city of Kramatorsk who helped Russia target a missile strike on a pizzeria last June has been jailed for life, prosecutors said Thursday.

Thirteen people including novelist Victoria Amelina were killed when a Russian ballistic missile tore through the popular "Ria Pizza" restaurant on the evening of June 27, 2023.

"A local resident was sentenced to life imprisonment for guiding the occupiers' missile attack on the pizzeria in Kramatorsk," the office of Ukraine's Prosecutor General said.

It said the man was recruited to carry out the task by an intelligence official in the Russian-controlled part of the eastern Donetsk region, who asked him to gather information about the restaurant.

"The convict agreed to the offer. In the city centre, he noticed cars with military licence plates in the car park and military themselves in the restaurant," it said.

The man then covertly recorded two videos of the site, which he immediately sent to his handler via Telegram before covering up evidence of his actions, it said.

"The man was sentenced to life imprisonment with confiscation of property for high treason," it added.

Kyiv has waged an intense crackdown on those suspected of having aided and abetted invading Russian forces since February 2022, many in its east and south.

The United Nations said last year Ukraine had opened more than 6,600 criminal cases "against individuals for collaboration and other conflict-related crimes" since the war began.