NEW DELHI: India has again issued a "red alert" in the national capital and in the cities of Mumbai and Chennai, following intelligence inputs that at least three to five Taliban militants have sneaked into the country to carry out terror attacks, Home Ministry sources said Friday.

The terrorists are targeting the Bombay Stock Exchange and the headquarters of a Hindu outfit, the sources said, adding the police forces have been put on high vigil following the inputs and efforts are on to nab the terrorists at the earliest.

The government had issued a similar alert a couple of weeks ago after being tipped off by the FBI. The alert was issued by the Indian Home Ministry to the states of Maharashtra, West Bengal, Delhi and Gujarat asking them to beef up security of all such vital installations and high-risk individuals -- like Gujarat Chief Minister Narendra Modi and Shiv Sena supremo Bal Thackeray.

This alert followed a similar warning which put nuclear installations across the country on high alert, amid fears that terrorists could target them.