It is being reported around 12 bombs have gone off in the troubled state of Assam in northeastern India.
At least 68 people have been killed, according to police reports, with more than 300 injured.
Security forces have been fighting a separatist insurgency there for decades, with some 20 rebel groups operating in the region.
While no group has claimed responsibility for the blasts, officials suspect the separatist United Liberation Front of Assam.
“The central government has provided military support to the government of Assam and we have repeatedly said they have to be alert to organisations like United Liberation Front of Assam who carry out these attacks,” said the junior Home Minister.
Intelligence officials say no other group could trigger so many blasts in so many places in such a quick coordinated fashion.
The explosions, which police say were hidden in motorcycles and scooters, all went off within an hour after 11 o’clock local time. Most of the blasts took place in the state capital Guwahati, where several busy market places were targeted.