Twelve Libyan officials have received sentences ranging between nine and 27 years in prison for their role in catastrophic dam collapses that killed more than 4,000 people last September.

Entire neighbourhoods in the city of Derna were swept away, and evacuation efforts were botched.

The convicted officials were responsible for managing water resources and maintaining the dams.

They were charged with crimes including negligence, premeditated murder and wasting public money, Reuters reported.

Three of the defendants were also ordered to repay money obtained through illicit means, the public prosecutor's office said. Four others put on trial were acquitted.

An international report in January said the dams gave way partly due to poor maintenance and governance during more than a decade of conflict in Libya.

A week after the disaster hit Derna, furious residents burnt down the mayor's home as they demanded answers. The whole city council was dismissed.

In the days after the floods, residents told BBC Arabic that evacuation orders focused on the wrong part of Derna, that no sufficient provision was made for where evacuated people should shelter and that some of the stay-at-home orders and curfews contradicted each other.

Locals also told the BBC that some people who were evacuated from the seafront because of fears of rising sea levels were moved to more dangerous areas that later flooded.

The water was brought by Storm Daniel, resulting in more than 400mm of rain to parts of Libya's north-east coast within a 24-hour period.

That is an extraordinary deluge of water for a region which usually sees about 1.5mm throughout the whole of September, as BBC Verify reported at the time.

Libya's National Meteorological Centre said the rainfall set a new record.

Since the ousting of long-time leader Muammar Gaddafi, Libya has been divided by power struggles and currently has two governments - a UN-recognised one based in Tripoli, and another in the country's east backed by warlord Gen Khalifa Haftar.