"Central intelligence wings and the union home ministry have alerted the state governments in northeastern states to keep a strict vigil in the run-up to Independence Day and thwart any attempt of separatist outfits to create violence," Tripura's inspector general of police Nepal Das told IANS.
He said: "Both the central and state governments have also asked the Border Security Force (BSF) to tighten security along the India-Bangladesh border to prevent trans-border movement of militants."
"Central para-military personnel, accompanied by bomb disposal units and dog squads, continued their search operations at airports, hotels, bus terminals, major markets and national highways," Das said.
Four northeastern states -- Tripura, Meghalaya, Mizoram and Assam -- share a 1,880 km border with Bangladesh, while India and Bhutan share a 643 km unfenced border.
In a separate directive, the director general of civil aviation has asked airport authorities to tighten the vigil in and around all airports in northeastern states.
"Entry of people inside airport terminal buildings, excluding aircraft passengers, has been barred till Aug 20. Several other security measures have also been taken in and around airports," Airport Authority of India director S.D. Barman said.
Seven separatist outfits -- including the anti-talk faction of the United Liberation Front of Asom (ULFA) -- of Assam, Manipur, Meghalaya, and Tripura have called a 17-hour general strike from midnight of Tuesday and boycott of Independence Day celebrations.
"We are fighting against colonial India and for this obligation of national sovereignty, we will fight for it to the end," a joint statement of militant groups said.
Signed by ULFA's publicity secretary Arunudoy Asom, the statement, e-mailed to media organisations, said: "The Indian government is trying to lure the people and the freedom fighters as well in the name of peace talks with the so-called Indian mainstream."
"We have experienced futile promises of the governments in Mizoram, Nagaland, Tripura, etc. and the present process of peace talks in Assam and Nagaland is nothing but dilly-dallying to our struggle of national self-determination," it added.
However, police authorities in the northeastern states said they are not aware of any such boycott call.
The Northeast Frontier Railway has also decided to cancel and reschedule all night trains through Assam and Tripura until Aug 17 for security reasons.
Agartala: The central government has alerted the northeastern states about possible militant strikes in the run-up to Independence Day celebrations on Wednesday.
First Published: Saturday, August 11, 2012, 16:07