A fire at a popular nightclub in India's coastal region of Goa has killed 25 people, local officials say.

Police had initially thought a gas cylinder in the Birch nightclub's kitchen exploded – but the region's chief minister said on Sunday that this had been ruled out and that indoor fireworks were now thought to be the cause of the blaze.

The venue, located near a popular beach, was packed with revellers who had come to hear a Bollywood DJ. Four members of the same Delhi family and 21 staff died, police said.

Four people have been arrested, including the nightclub's manager, and an arrest warrant for the owner has also been issued.

Goa is a former Portuguese colony on the Arabian Sea. Its nightlife, sandy beaches, and resorts attract millions of tourists annually.

Eyewitnesses told the BBC of scenes of panic in the bustling nightlife area. One said that he had been outside the club on what was a usual Saturday night with holidaymakers enjoying themselves when he heard screams.

Though the main entrance is wide, the crossing over a small lake leading to the main structure is narrow and that made it difficult for firefighters to reach the spot. The BBC saw what appeared to be melted remains of chairs, tables, and plants in one corner of the club.

Goa's chief minister Pramod Sawant told journalists three people had died from burns, while most of the others had died of suffocation. Six people are in a stable condition in the hospital.

Officials said 20 of the workers who died were from the Indian states of Jharkhand, Uttarakhand, Maharashtra, Assam, Uttar Pradesh, West Bengal, and Karnataka. One worker was from Nepal.

On Sunday, emergency teams were combing through the charred wreckage. An inquiry into the cause of the fire has been launched, Sawant said, and a full report into the incident will be released within a week.

India's Prime Minister Narendra Modi called the Goa fire deeply saddening in a post on social media. Some opposition politicians told the BBC that stricter regulations were needed to avoid such tragedies, alleging that newer clubs were opening too frequently without proper safety checks.

In recent years, India has experienced several deadly fires at entertainment venues, including a fire in Hyderabad that killed 17 in May.