The famed Sri Krishna temple in Guruvayur, Kerala received a threat call, following which its security has been tightened, police said.
The temple officials received a call from an unknown person in the morning and threatened that the shrine would be "destroyed".
The caller alleged that there was corruption in the administration of the temple, police said.
Based on a complaint from the temple management, a case was registered and investigation was on. Steps were on to collect call detail record, they said.
More police personnel were deployed in the temple premises and bomb squad intensified checks, police said.
The Guruvayur Sri Krishna temple is one of the major pilgrimage centres in the Kerala, visited by millions of devotees every year.