Shillong,  After the arrest of 37 jihadi cadres in little over a month in Assam for their alleged links with the Al-Qaeda in the Indian Subcontinent and the Ansarul Bangla Team, a Bangladesh-based terror outfit, the northeastern states which share border with Bangladesh have stepped up the vigilance.

Police and intelligence officials in Agartala and Shillong on Friday separately said the strict surveillance over the jihadi activities have further intensified and intelligence inputs between the various security agencies being shared for taking further course of action.

Meghalaya Director-General of Police Lajja Ram Bishnoi said in Shillong that after getting the inputs of jihadi activities in Assam, directions have been given to all the police stations and outposts particularly in those areas having borders with Bangladesh to keep a close watch on the bordering villages.

"Our intelligence officials and police personnel are alert over the jihadi activities," the police officer told the media.

In Agartala, a senior police officer said that Border Security Force (BSF) troopers and the people of the bordering areas have been alerted to keep a close watch in their respective areas.

The three cadres, who were recently arrested in Tripura for their links with the banned Jamaat-ul-Mujahideen Bangladesh (JMB), have been subsequently taken to Assam as part of the investigation against the jihadi group.

Intelligence officials found links between these three persons with the four arrested in Bhopal in April for their affiliation to the JMB.

Top central and Tripura intelligence officials interrogated Imran Hussain, 25, an Imam, Abul Kashem 32, a teacher, and Hamid Ali, a farmer, who were arrested from Jatrapur, a village in Sepahijala district of Tripura along India-Bangladesh border.

They were booked under the Unlawful Activities Prevention Act (UAPA).The Investigation Agency filed charge-sheet against eight of the 37 arrested in Assam for alleged links with fundamentalist organisations.

Of the eight, seven are from western Assam's Barpeta district and one from Tripura.

The Assam government had handed over the cases of "jihadi terror modules" to the NIA after the preliminary investigation.

Four Indian northeastern states of Tripura (856 km), Meghalaya (443 km), Mizoram (318 km) and Assam (263 km) share an 1,880-km border with Bangladesh.

Vast areas of the sensitive borders with Bangladesh remain unfenced.