Bhutan's military has reportedly killed at least 90 Indian separatists in the three days since launching an offensive to force the militants out of the kingdom.
Indian military officials say between 90 and 120 Indian separatists have been killed by Bhutan's Royal Armed Forces since Monday.
Some 6,000 Bhutanese soldiers launched their first-ever modern military operation to drive out Indian rebels. The militants have been using the tiny kingdom as a base to carry out hit-and-run guerrilla strikes in India, where they are fighting for independent homelands in the northeast.
Indian officials also say they have in custody another 10 militants. Some were handed over to them by the Bhutanese military. Others were caught trying to sneak back into India.
The operation has the support of the Indian government. But Thinley Penjor, Bhutan's deputy head of mission in New Delhi, stresses that it is not a joint military operation.
"It's the Bhutan Army, which is handling the situation inside the country," he said. "But I understand that there is a very close understanding once these militants cross into the Indian territory, how they're handled."
But Mr. Penjor says the Indian military is helping evacuate injured soldiers. The military has also fanned out along the border in the states of Assam, Arunachal Pradesh and West Bengal the country's remote northeast to assist.
The United Liberation Front of Asom, the National Democratic Front of Bodoland and the Kamtapur Liberation Organization were founded in the late 1980's as separatist movements. But now their demands range from independence to simply more autonomy for ethnic Bodos and Assamese in India.