Air defense systems were repelling missile attacks in the early hours on Monday in the Kyiv region, local authorities said, after air raid alerts were issued throughout all of Ukraine by emergency services.

"Air defenses are at work!" Kyiv's regional administration wrote on the Telegram messaging app, after reports of explosions heard in the region.

"Keep calm! Stay in shelters until the air alarm goes off!"

Ukrainian media also reported blasts in the Dnipropetrovsk and Sumy regions.

Reuters was unable to independently verify the reports ot blasts.