Security forces across the country went on high alert on the eve of Independence Day in view of threats by militant outfits to disrupt the celebrations even militants killed six bus passengers in a blast in Manipur and police in Kerala on Wednesday night defused two crude bombs planted in a bus.

As many as 52 additional companies of the Central Reserve Police Force have been deployed in various parts of the country for maintaining law and order during the Independence Day functions on Friday. Among these, 20 companies have been deployed in Srinagar, 15 in Delhi, 10 in Assam, two in Meghalaya and five in Jharkhand, which is plagued by Maoist violence.

In the capital, where Prime Minister Atal Bihari Vajpayee will unfurl the national flag and address the nation from the ramparts of the Red Fort on Friday, police and paramilitary forces have been deployed in strength. Sharp shooters took up positions on high-rise buildings in the vicinity of the historic venue and the entire area has been declared out of bounds for the public.

Air traffic in Delhi and some adjoining areas will be suspended for six hours from 0400 IST on Friday and two helicopters will be deployed for aerial surveillance to prevent any terror strike like the September 11, 2001 attack in the United States.

In Jammu and Kashmir, intelligence agencies have intercepted wireless messages of militants suggesting suicide attacks in the Jammu region. A multi-tier security ring had been thrown around the city of temples in coordination with the army.

Extra security measures were being taken in the Northeast, especially in Imphal where militants killed six bus passengers and injured 15. Patrolling on National Highways and militant-infested areas have been intensified and additional troops posted in sensitive areas and around vital installations. Running of trains on the North East Frontier Railway Zone will be suspended for two days from Thursday night.

In Gujarat, security was tightened in the wake of intelligence reports that some youth from the state had gone to Pakistan-occupied-Kashmir and would return to carry out suicide attacks on Independence Day.

Maharashtra, which has seen a series of crude bomb explosions lately, was also put on alert amidst reports that activists of the banned Students Islamic Movement of India were planning more attacks.

Security arrangements in Rajasthan, Uttar Pradesh and Haryana were also tightened and all entry and exit points to the capital were being manned by security personnel.