The authorities are searching for anyone who may still be trapped under the rubble.

The sources say a school, on a holiday break, was hit but the federal government has not commented.

Monday's dron strike on the Zawiya refinery was the third such incident in two days.

Firefighters are trying to contain a blaze at a large petrol tank west of the capital, Tripoli, which was targeted by unknown attackers.

Hakainde Hichilema was a shoo-in for a second term but the controversy following Edgar Lungu's death has dented his chances.