The PULF militants entered India through west Tripura's Sonamura border on July 15.

According to the Tripura police chief, the PULF has also forged links with Pakistan-based militant groups Lashkar-e-Taiba and Jaish-e-Mohammed.

The officer in charge of West Agartala police station, Subrata Chakraborty, said: 'The PULF separatists have admitted during interrogation that they had gone to Bangladesh through Myanmar in March this year.'

Rahaman reportedly said PULF cadres had held meetings with ISI representatives Rafiqul Islam and Mohammad Jafar at Cox's Bazar in south-east Bangladesh.

'The ISI agents told the PULF that they would provide sufficient money and arms to continue violence in India's northeast region,' the arrested rebels told police interrogators.

'PULF was trying to destabilise the northeast in collaboration with other Islamic groups based in the region and in Bangladesh,' Chakraborty told journalists.