Kolkata, Feb 13 (IANS): Four persons were killed and ten others severely injured after a helium gas cylinder of a balloon seller exploded at Jaynagar in West Bengal's South 24 Parganas district.

The explosion took place at a gathering on Sunday night on the occasion of a fair at Jaynagar.

Two of the four killed in the explosion were minors.

Muchiram Mondal (35), the balloon seller, whose helium cylinder exploded, died on spot. The other three, who died in the explosion have been identified -- Shahin Mollah (13), Abir Gazi (8) and Kutubuddin Mistri (35).

A huge police contingent led by the inspector-in-charge of Jaynagar Police Station Rakesh Chakraborty reached the spot immediately. The bodies of the four deceased had been sent for post-mortem,

The injured people were taken to the nearby Baruipur hospital. The condition of some of them was saif to be critical.

The sub-division police officer of Baruipur Atish Biswas said the police are investigating how the explosion had taken place.