One person killed, at least 31 injured in nightclub blast in Azerbaijan capital - AP

An explosion struck a nightclub in Azerbaijan's capital Baku early on Sunday, setting off a fire that killed one person and injured 31, the Associated Press reported.

The explosion was believed to have been caused by a gas leak and investigations were ongoing, the AP said, citing an Interior Ministry spokesperson.

"Very sad news about casualties as a result of explosion at the club downtown Baku," US Ambassador Khazar Ibrahim tweeted. "My condolences and prayers."

Some 24 of the injured had been hospitalised, most with burns, the AP quoted a Health Ministry spokesperson as saying.

Azerbaijan's health ministry did not immediately respond to a Reuters request for comment outside working hours. The interior ministry could not immediately be reached.

The country's emergency services were called to the club at 03:00 (23:00 GMT on Saturday) and extinguished the fire before it could spread, the AP said, citing a statement from the department.

Never miss a story. Choose from our range of newsletters to get the news you want delivered straight to your inbox.