Amidst fears of attacks by militants and strike call by insurgents in the Northeast, security forces across the country were put on high alert, particularly in Delhi and Jammu and Kashmir, on the eve of Republic Day.

In the national capital, President A P J Abdul Kalam will take salute at the historic Rajpath in the presence of the country's top leadership, including Prime Minister Atal Bihari Vajpayee and Deputy Prime Minister Lal Kishenchand Advani.

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A multi-layered security blanket has been spread around the city. The lawns flanking Rajpath, India Gate and Red Fort have been sealed and hundreds of security personnel are maintaining a strict round-the-clock vigil.

All the buildings flanking the 8km route have been taken over by security personnel to prevent terrorists from using rocket launchers or missiles to target the R-Day parade.

Security has also been beefed up at Indira Gandhi International Airport, vital installations, around prominent hotels, tourist spots and other areas in view of intelligence reports about specific threats to these places.

In Delhi, three Lashkar-e-Tayiba terrorists allegedly planning disturbances during Republic Day celebrations were arrested. The arrests took place at Lakshmi Nagar area in east Delhi at around 5am, Additional Commissioner of Police (Special Cell) Karnal Singh told reporters.

Three kilograms of high explosives, two electronic detonators, four ABCD timers and four rocket-propelled grenades were recovered from them. The group may have been planning to strike in the capital along with another module on Monday. A hunt is on to nab their associates.

In Jammu and Kashmir, security forces have been put on high alert and additional troops mobilised amid fears that terrorists may carry out suicide attacks.

The Maulana Azad Stadium in the state's winter capital Jammu, venue of the main function where Governor S K Sinha will take the salute, has been sealed off and sharp shooters and commando units positioned around it. Security measures have also been tightened around temples and vital government and security installations.

In the wee hours of Sunday, security forces recovered 25kg of RDX, a Chinese-made rocket launcher, 109 UBGL grenades, 12 Rocket Projectile Guns, 35 RPG boosters, 36 hand grenades, seven pistols, 18 IEDs, seven electronic detonators, 90 rounds of sniper ammunition and 1,040 rounds of AK ammunition from Srinagar. Arms and ammunition were seized from some other places in Kashmir too.

In order to thwart any attempts by militants to disrupt Republic Day celebrations in Srinagar, a three-tier security cover has been thrown around all the venues of celebrations, including the Bakshi Stadium where the main function will be held in the Kashmir valley.

The first ring of security covers the outskirts of the city to prevent militants from sneaking in or their couriers from bringing in arms and ammunition, CRPF Deputy Inspector General (counter insurgency operations) T S Dhillon told PTI in Srinagar.

The next ring takes care of area dominance and sanitisation to eliminate threats already present in the vicinity of the venues, Dhillon, who is in-charge of the operations north of Jhelum River, said.

The innermost security ring is entrusted with securing the venues of the functions.

Security forces have almost completed sanitisation around all the venues in the Kashmir valley, official sources said adding pedestrians and passengers of vehicles coming into the summer capital are being frisked at random.

Late on Sunday evening, militants ambushed a mini-bus of the Border Security Force near Haigam on the Srinagar-Baramulla highway. BSF spokesman Tirath Acharya said Deputy Commandant Dr Niranjan Paul was killed in the attack. In another incident in the evening, militants hurled a grenade at a police station in Srinagar damaging the window panes of the building.

The All Parties Hurriyat Conference led by Abbas Ansari has asked people to remain indoors while the faction led by Syed Ali Shah Geelani has asked them to observe a complete strike.

Extra security measures are being taken in the Northeast where insurgents have called for a general strike.

In Meghalaya, special operations are being carried out in some areas in the backdrop of repeated attacks on security personnel in the last few days. Garo Hills is the focus of the joint operation by Meghalaya and Assam police personnel along with the Central Reserve Police Force.

Additional troops have been deployed in Assam and a round-the-clock vigil is being maintained. Patrolling on National Highways, along railway tracks and militant-infested areas has been intensified with additional troops posted in sensitive areas and vital installations.

Security forces in Nagaland, Tripura and Manipur are on alert.

Extra security measures are being undertaken in some other states, particularly Maharashtra, Gujarat, Rajasthan, Uttar Pradesh and Tamil Nadu.

With inputs from Mukhtar Ahmad in Srinagar