At least five blasts, including two by improvised explosive devices (IED), took place in Assam within one hour on Sunday as India marked its 71st Republic Day.
The two IED blasts took place in Dibrugarh and one grenade blast each were reported in Sonari, Duliajan and Doomdooma, Hindustan Times reported quoting officials.
No one has been injured in the blasts. Police are investigating the incidents.
Strongly condemning the bomb blasts, Assam Chief Minister Sarbananda Sonowal said, "This cowardly attempt to create terror on a sacred day only exhibits the frustration of the terror groups after their total rejection by the people. Our Govt will take the sternest action to bring the culprits to book."
The United Liberation Front of Asom (Independent) (ULFA-I) is suspected to be responsible for the blasts.
The banned outfit had issued a call for a "general strike" on Sunday asking citizens to abstain from the Republic Day celebrations in the state and remain indoors.
The blasts come days after 644 militants from eight rebel outfits laid down arms in front of Sarbananda Sonowal at a ceremony in Guwahati. They included 50 ULFA-I cadres.
Militant outfits in Assam and rest of the northeast routinely call for a boycott on Republic Day and Independence Day and carry out minor blasts.