Drones attacked Ukraine's western city of Lviv early Tuesday and explosions rang out as the city mayor said a strike had set fire to a warehouse.

Several waves of drones buzzed overheard starting around 0130 GMT and an AFP journalist heard numerous explosions and movements of heavy vehicles through the streets during the nightly curfew.

The city's mayor, Andriy Sadoviy, wrote on Telegram that "air defences are operating in our region", telling people to seek shelter.

Sadoviy later added: "Explosions are heard. As a result of a strike on Lviv, there is a fire at an industrial warehouse. All the necessary services have gone to the site."

Ukraine's air forces wrote on Telegram that "the threat of Shahed (drones) remains in the Lviv region. Air defences are operating".