Ukraine has carried out a significant drone attack, claiming to have struck a Russian oil refinery as part of its strategy to weaken Moscow’s energy infrastructure. The strike is seen as an attempt to disrupt fuel supplies critical to Russia’s military operations.

A Russian drone attack on a residential block killed nine people including three elderly couples in the eastern Ukrainian city of Sumy, officials said on Thursday. Moscow has pummelled Ukrainian cities with dozens of drones or missiles almost daily since it invaded in early 2022.

Russia launched a barrage of drones in an overnight attack on Ukraine on Friday, killing three civilians and damaging residential and commercial buildings, officials said.