Agartala/Aizawl/Imphal, Jan 25 (TIWN / IANS) The union home ministry has alerted the northeastern states over possible terror attacks in the run-up to the Republic Day Monday, an official said Sunday.

"The home ministry has alerted the northeastern states to maintain strict vigil in the run-up to the Republic Day and foil any attempt by separatist outfits to create a vicious situation," Inspector General of Tripura Police (Police Control) Nepal Das told IANS.

"The central and state governments have also asked the BSF (Border Security Force) to further strengthen vigilance along the India-Bangladesh border to prevent trans-border movement of militants," he said.

The BSF, Central Reserve Police Force (CRPF), Tripura State Rifles and other central paramilitary personnel accompanied by bomb disposal and dog squads continued search operations at airports, hotels, bus and railways terminals, markets, congested locations and national highways.

Four northeastern states - Tripura, Meghalaya, Mizoram and Assam - share an 1,880-km border with Bangladesh, while India and Bhutan share a 643-km unfenced border.

Four states of the region - Mizoram, Manipur, Nagaland and Arunachal Pradesh - also share a 1,640-km unfenced border with Myanmar.

Arunachal Pradesh shares an 1,080-km unfenced border with China.

Several separatist outfits, including the United Liberation Front of Asom (ULFA), have called for a 24-hour general strike from Jan 25 midnight and for boycotting the Republic Day celebrations. They have mailed statements to media organisations in this regard.

"We are yet to get any confirmation that the militant outfits have called a strike and boycott of the Republic Day celebrations," Das added.

The Northeast Frontier Railway has also taken up security measures regarding the running of trains in Assam and Tripura.

An official of the Airports Authority of India said that entry of people, except passengers, into airport areas across the northeast has been barred and the restrictions would continue till Jan 27.

In Manipur, a senior police official said round-the-clock patrolling is being carried out in different places of the state specially in four valley districts of Imphal East, Imphal West, Thoubal, and Bishenpur.

More than 12 IEDs (Improvised Explosive Devices) have exploded in different places of Imphal town and other places in the past eight days, the official said, adding that no one was hurt in these blasts.

In Mizoram, Assam Rifles and Mizoram Armed Police have strengthened security across the mountainous state, bordering Myanmar.