Agartala, Dec 23 (IANS): Eleven National Liberation Front of Tripura (NLFT) militants have surrendered to security forces in Tripura, police said Sunday.

They included the outfit's self-styled area commander Suran Debbarma.

"The extremists sneaked into Indian territory from Bangladesh before surrendering to the BSF (Border Security Force) Saturday night," a police spokesperson told reporters here.

The guerrillas crossed the border at Karbook, 125 km from here, taking advantage of the mountainous terrain.

Debbarma led the state's biggest massacre of 21 Tripura State Rifles troopers Aug 20, 2002 at Hirapur in western Tripura. He was wanted for many crimes including killings, the police official said.

Police said the men, who fled their camps in Chittagong Hill Tracts in Bangladesh last week, also surrendered some arms and ammunition, including AK series rifles. The BSF is interrogating them.

Tripura's two banned groups -- NLFT and All Tripura Tiger Force -- have set up bases in Bangladesh.

Tripura shares an 856-km-long border with Bangladesh, some of it unfenced and running through dense forests, making it porous and vulnerable.