At least 51 people have been killed and more than 100 injured in a nightclub fire in North Macedonia, officials say.

The blaze is said to have started around 02:30 (01:30 GMT) at the Pulse club in Kocani, a town around 100 km (60 miles) east of the capital, Skopje. Footage posted on social media shows the building engulfed in flames.

As many as 1,500 were said to have been attending a concert by the band DNK, a hip-hop duo popular in the country.

Interior Minister Pance Toskovski said that according to initial reports, the fire started from sparks caused by pyrotechnic devices.

He told reporters in front of the Kocani police station that sparks then hit the ceiling made of highly flammable material, before the fire spread through the club. He said some arrests had been made.

Footage shows the band playing on stage when two flares go off, sparks then catch on the ceiling before rapidly spreading.

Prime Minister Hristijan Mickoski wrote in a statement on Facebook that the government was "fully mobilised and will do everything necessary to deal with the consequences and determine the causes of this tragedy."

He called it a "difficult and very sad day" for the country which had now lost so many young lives.

The hospital in Kocani initially reported 90 admissions, with many suffering severe burns. Some of the injured have since been transferred to hospitals in Skopje for further treatment.