The All-Tripura Tiger Force (ATTF) was originally founded as All Tripura Tribal Force on July 11, 1990, by a group of former Tripura National Volunteers (TNV) militants, who under the leadership of Ranjit Debbarma dissociated themselves from a faction of the TNV led by Lalit Debbarma which surrendered arms in accordance with the August 1988 Accord concluded between the TNV and the Union government.

The outfit rechristened itself as All-Tripura Tiger Force by substituting the word 'Tribal' with 'Tiger' sometime in 1992. It was initially a small group of tribal militants who operated in pockets of North and South Tripura districts. Gradually, it began mobilising manpower by recruiting tribal youth and enhancing the firepower of its cadres. By 1991, it emerged as a formidable insurgent group in Tripura.

More than 1,600 cadres surrendered by March 1994, under an amnesty scheme offered by the state government. A group of cadres which did not surrender revived ATTF. It was subsequently banned in April 1997 under the Unlawful Activities (Prevention) Act, 1967. Over the years, ATTF either formed or was associated with fringe terrorist/criminal groupings such as the Tripura Tribal Youth Force (TTYF), the Tripura Liberation Organization (TLO), the Tripura Young Rifle (TYR), the Tripura Lion Force (TLF) and the Tripura National Army (TNA). Most of these groups have ceased to exist.

The outfit's objectives are:

1. Expulsion of all Bengali-speaking immigrant settlers who entered Tripura after 1956.
2. Restoration of land to tribals under ‘Tripura Land Revenue and Land Reforms Act’, 1960.
3. Removal of names of migrants who entered Tripura after 1956 from the electoral roll.

The outfit is headed by its president, Ranjit Debbarma. Chitta Debbarma alias Bikash Koloi is the vice-president and Upendra Debbarma is its organisation secretary. Malinjoy Reang functions as the outfit's publicity secretary, while Subodh Debbarma is its communications secretary. Asit Debbarma is the finance secretary. The political wing of the ATTF – Tripura Peoples' Democratic Front (TPDF) – has reportedly set up a parallel government in the remote areas of the state.

Ranjit Debbarma has taken refuge in Bangladesh. The ATTF headquarters is located at Tarabon in Bangladesh. It also serves as the makeshift headquarters of Arabinda Rajkhowa, chairman of the United Liberation Front of Asom (ULFA). ATTF cadres are reported to have received training in the Chittagong Hill Tracts (CHT) of Bangladesh and the outfit has a number of bases there. More than 70 per cent of ATTF cadres are located in Bangladesh.

The community-wise break-up in ATTF is: Debbarma- 70 per cent, Jamatia- 10 per cent, Reang- 10 per cent, Tripuri – 5 per cent and others- 5 per cent. About 90 per cent of the top ranking ATTF cadres are Hindus and the rest are Christians. The outfit's cadre strength is reported to be about 600.

ATTF has resisted official attempts for a negotiated settlement of the insurgency. On April 22, 2004, however, Ranjit Debbarma, laid down three conditions for peace talks:

• Those who entered Tripura after 1949 and whose names did not figure in the Voters list of 1952 should be declared as foreigners;
• The issue of sovereignty should be point of discussion in the peace talks; and
• A representative of the Unrepresented Nations and Peoples Organization (UNPO) should be present during the peace talks.