Police said that the message, which was received on Jul 7, had been traced to a Gulf country.
Police also said that they were making a huge efforts to identify the source of the message with the help of internet service providers.
However, the message sender did not reveal the names of the cities in Kerala, where they had planned to plot the bombs.
Police said such threatening messages were taken 'very seriously.'
Without any delay, necessary steps had been taken to enhance security, said police.