Ukraine said on Friday it had struck a Russian oil refinery and a microchip factory in a huge drone attack that caused fires at the refinery's production facilities and an oil pumping station. Russia said hours earlier that its forces had repelled an overnight drone attack,

The General Staff of Ukraine's Armed Forces confirmed an attack overnight that hit Russia's Ryazan Oil Refinery and the Ryazan Thermal Power Plant, leaving them ablaze Thursday morning.

The energy giant is spending nearly $50 billion to expand the Tengiz oil field, allowing it to pump one million barrels a day.

Chevron said on Friday it had started production at a $48 billion expansion of the giant Tengiz oilfield which will bring its output to around 1% of global crude supply.