Following a series of attacks, carried out by tribal insurgent groups of Tripura, on Bengali settlers, the United Bengali Liberation Front (UBLF) was formed in October 1999 as a Bengali outfit to counter these attacks.

The UBLF militants were involved in a number of terrorist activities, including kidnappings, extortion, arson, bombing and killing of tribals. The UBLF had been extorting taxes from a variety of sources. Intelligence reports indicate that the outfit raised huge funds from a number of Calcutta-based business groups dealing in tea, rubber, timber and construction in Tripura. Besides, the UBLF militants had been extorting taxes from tribal State government employees. The UBLF also secured more than 100 AK-47 and AK-56 rifles from some militant groups operating in the North-east and tried to procure more weapons and high power explosives from Bangladesh.