A delivery cyclist wearing a face mask cycles down a street in Kyiv, Ukraine on Sept 20 on a day with poor air quality. (AP)

Authorities in Ukraine have advised residents in the capital Kyiv to stay indoors as air pollution, partly caused by fires in the region, blanketed the city.

Kyiv authorities warned about sharp and "temporary deterioration" of air quality in Kyiv on Sept. 20 due to the accumulation of harmful substances. The likely cause is fires in Kyiv Oblast that released large amounts of dust particles in the air,

European Commission President Ursula von der Leyen announced a loan of up to 35 billion euros ($39 billion) for Ukraine during a visit to Kyiv on Friday, saying it was needed to defend the country against Russian attacks and help it get through the winter.

Russia continues to target the war-torn country's energy infrastructure, leaving parts of the east in darkness for hours at a time.

European Union chief Ursula von der Leyen is traveling to war-ravaged Ukraine on Friday with the promise of 160 million euros ($180 million) in fresh energy funds to get the nation through the winter.