The Indian army conducted an operation against separatist militants along the country’s northeastern border with Myanmar early on Tuesday, inflicting “significant casualties” on the rebels, according to an army statement.

While the exact number of militants killed in the operation -- conducted just days after 20 Indian troops were killed in an ambush on a convoy in the state of Manipur -- has not yet been revealed, local media reported that up to 100 militants were killed. The region, along with the neighboring state of Nagaland, has long been a hotbed of insurgency led by dozens of separatist militant groups, who have frequently targeted Indian security forces.

According to the army statement, the attack was in response to "credible and specific intelligence" about further attacks inside Indian territory.

“This is a message for all countries, including Pakistan, and groups harboring terror intent towards India. A terrorist is a terrorist and has no other identity. We will strike when we want to,” Rajyavardhan Rathore, a junior information and broadcasting minister in the Narendra Modi-led government, told the Indian Express.

The operation, which targeted two separate groups of militants in two locations along the border, lasted for several hours and was declared over only on Tuesday afternoon, NDTV -- an Indian news network -- reported, citing unnamed sources.

“Indian Army is in communication with the Myanmar authorities on this matter,” Indian officials said, in the statement, without providing further details.

Rathore said that the operation involved “our special forces crossing the border and going deep into another country,” but it is not clear from the official statement whether Indian troops had crossed over into Myanmar for the "much-needed" operation.

“Both camps were struck and were completely annihilated. The special forces returned without a single casualty,” Rathore told the Indian Express.

The offensive, which is being touted as “extremely bold,” came just days after militants armed with rocket-propelled grenades and explosives killed 20 Indian soldiers in the restive state of Manipur.

“In view of the imminent threat, an immediate response … was conducted to counter these planned assaults," the statement said.