GUWAHATI, August 24: The Harkat-ul-Ansar (HUA), a dreaded militant outfit of Kashmir backed by Pakistan's Inter-Services Intelligence (ISI), has intensified its activities along the Indo-Nepal border to destabilise the Northeast and the neighbouring states of the region. According to highly-placed official sources, the security forces have unearthed the "nefarious design" of the militant group following recovery of a letter in which the Mohna unit of the organisation urged the members to create unrest in West Bengal and the Northeast. The official sources further said that the letter which was addressed to one Nazimuddin of Kakarbhita near Dhulabari said that since Siliguri is a vital place for communication to the Northeast, members should concentrate on the area. "In the letter, the self-styled general secretary of the Mohna unit urged the leadership to bring sophisticated weapons for two militant groups of the North-east," the sources said, adding that the secretary, however, did not name the militant groups. They revealed that according to the letter an important meeting was held at Damak Madrassa, located somewhere along the Indo-Nepal border in presence of 20 members of the group where they had decided to go for a Jehad in Bihar, Uttar Pradesh, West Bengal and in the Northeast. "With the recovery of the letter the intelligence agencies have been activated to thwart the design of the outfit. Moreover more forces have been deployed," the sources said. After the development a series of operations were carried out in Hasimara and Jerigaon areas of West Bengal, but no one was arrested. Commenting on the Harkat-ul-Ansar shifting its activities along the Indo-Nepal border, they expressed the view that the outfit was controlled by the ISI and now it had intensified its activities in the area. Another important fact is that Nepal is a hot-bed of the ISI and taking advantage of population structure the outfit has become active in the region, they informed. The sources further informed that the ULFA leadership had already held discussions with the militant group to procure arms and ammunition.