Thiruvananthapuram, March 21 (IANS) Twenty-seven passengers had a narrow escape Sunday when an explosive, a cocktail of sulphur, potassium chlorate and aluminum powder, was found in the cargo section of a Kingfisher flight after it landed here from Bangalore.

A Central Industrial Security Force (CISF) official reportedly discovered the crude explosive, the size of a cricket ball and wrapped in a Malayalam newspaper, shortly after the plane landed here at 8.25 a.m.

The discovery triggered panic alarms in Bangalore and Thiruvananthapuram, leading to a high-level investigation on how it got past the many layers of security.

'It is not a bomb but certainly one which is explosive in nature. We have decided to register an FIR (first information report),' Thiruvananthapuram police chief M.R. Ajith Kumar said.

The aircraft was quickly cordoned off and searched before it was allowed to return to Bangalore in the afternoon.

Kerala Inspector General of Police A. Hemachandran said: 'The explosives were small in quantity. Yes, if the quantity was large, then things would have been different. We have have already identified the passengers, crew and workers (who attended to the plane) and begun the probe.'

Ajith Kumar said: 'We are investigating how this happened. Certainly this is a security lapse.'

A civil aviation ministry official told IANS in New Delhi: 'We have ordered a probe into this serious lapse of security. The Bureau of Civil Aviation Security (BCAS) is investigating.'

BCAS is the regulatory authority for civil aviation security in India.