The ICG, Intelligence Bureau, police, customs, Navy and other agencies are further probing into the seizure.
"The Indian Coast Guard ship 'Samudra Pavak' intercepted and apprehended a merchant vessel carrying approximately 1,500 kg of heroin valued at about Rs 3,500 crore off the coast of Gujarat," a statement by defence PRO Abhishek Matiman said.
"Based on intelligence inputs, the vessel was intercepted at around 1200 hrs yesterday. This is the largest single haul of narcotics seized till date," the statement said.
An official of the Porbandar Special Operations Group said the ICG has called them for a meeting regarding the drug haul at around 4 pm today.