NEW DELHI, Aug 14: India sounded its highest security alert on Saturday and deployed tens of thousands of police and troops, especially in flashpoint areas such as Kashmir, on the eve of Independence day celebrations, officials said.

The capital was transformed into a virtual fortress with more than 10,000 federal troopers out on the streets with the city's 55,000 policemen ahead of Sunday's celebrations.

Commandos installed a bullet-proof glass enclosure at the 17th-century Red Fort, where Prime Minister Manmohan Singh will deliver his maiden Independence Day address, a police spokesman said.

Sharp-shooters and bomb squads took positions Saturday as thousands of school children rehearsed outside the Mughal-built complex after the police shut down the nearby usually-bustling Chandni Chowk markets and deployed officers on rooftops of high-rise buildings.

Commandos cruised through Delhi in vehicles with mounted machineguns, witnesses said.

The nationwide security alert comes amid fears of attacks by Kashmiri guerrillas and rebels from India's northeastern states who mark August 15 as "black day."

Home ministry officials said intelligence reports warned of possible attacks by the pan-Islamic militant groups Jaish-i-Mohammad and Lashkar-i-Taiba during India's independence day celebrations on Sunday.

The two groups were blamed for a December 2001 attack on the Indian parliament that nearly set off a war with rival Pakistan.

Air force fighter jets and attack helicopters were placed on standby in New Delhi as cities such as Bombay, Madras and Calcutta deployed their entire police force on red security alert, the home ministry officials said.

"The programme starts 7:00 hours but the Delhi skies will be turned into a no-fly-zone for five hours from 5:00 am tomorrow," an official from the airforce's Western Air Command told AFP.