The military coup almost two years ago has sparked renewed fighting with long-established ethnic rebel groups, as well as with dozens of "People's Defence Force" groups that have sprung up to oppose the junta.

The bombing by five jets on Tuesday evening killed five fighters at the headquarters of the Chin National Front (CNF), which claims to represent the mainly Christian Chin minority in western Myanmar, spokesman Salai Htet Ni told AFP.

"They dropped seven bombs... Some of our houses were destroyed from their air strike... One bomb landed on the Indian side," he said.

Local media also reported five fighters had been killed and that one bomb landed in Champhai district, in India's Mizoram state.

But Indian police said the bomb had actually landed directly in the dry riverbed that marks the international boundary.

"Our initial investigation has revealed that there is no damage to any (Indian) life or property," Lalrinpuia Varte, police superintendent of Champhai district, told AFP.

"Farkawn village, which is about eight to nine kilometres (five to six miles) from the international border, is the closest to where the incident happened."

The CNF's fighters have dwindled in recent years, and it signed a ceasefire with the military in 2015.

But in May last year it signed an agreement with a shadow government dominated by lawmakers from Aung San Suu Kyi's National League for Democracy (NLD) that is working to overturn the coup.

Coup leader Min Aung Hlaing has justified his power grab by claiming electoral fraud in November 2020 elections won by Suu Kyi's NLD.

International observers said at the time the polls were largely free and fair.

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