Police on Wednesday stepped up security in Imphal after separatist guerrillas launched a grenade attack at the official residence of Manipur Chief Minister Okram Ibobi Singh.
A police spokesman said activists of the People's Revolutionary Party of Kangleipak (PREPAK) tossed the grenade late on Tuesday.
"The grenade exploded inside the complex of the residence. Luckily no one was injured," a police official said. The chief minister was in New Delhi when the attack took place.
"We have intensified security in the capital and particularly in and around the chief minister's residence and other vulnerable locations," the official said.
The PREPAK, an outlawed rebel group fighting for an independent homeland for the majority Metei community in the state of 2.4 million people, has claimed responsibility for the grenade attack.
Singh had survived two previous assassination attempts by rebels. In May, militants ambushed his convoy but he escaped unhurt.