ISIS India head and one of his associates were arrested in Assam's Dhubri district on Wednesday after they crossed over from Bangladesh, police said.
In a statement, Assam Police Chief Public Relations Officer Pranabjyoti Goswami said they were apprehended from Dharmasala area by the Special Task Force (STF) following a tip-off.
They were later brought to the STF office in Guwahati, he added.
"The identity of both of them was ascertained and it is found that accused Haris Farooqi alias Harish Ajmal Farukhi of Chakrata, Dehradun is the head of ISIS in India," Goswami said.
His associate Anurag Singh alias Rehan of Panipat got converted to Islam, while his wife is a Bangladeshi national, he added.
"Both of them are highly indoctrinated and motivated leaders/members of ISIS in India. They had furthered the cause of ISIS in India through conspiracies to carry out recruitment, terror funding and terror acts using IEDs at several places across India," the CPRO said.
He further said that several cases are pending against them at NIA, Delhi, ATS and Lucknow among other places.
"STF, Assam, will hand over the accused to NIA for taking up further legal actions against these fugitives," the police official said.
Goswami said information was received from sister agencies that two top-rung leaders of ISIS in India, who were camping in Bangladesh, would cross over to the country at the Dhubri sector to carry out sabotage activities.
Based on the input, a team was deputed to locate and apprehend them.
"A manhunt was launched in the international border area to nab the culprits. At around 4:15 am of March 20, the accused persons were detected at Dharmasala area of Dhubri after they had crossed the international border," it added.