Delhi,Mumbai,Kolkata and Gujarat have been put on high alert following intelligence inputs that Taliban-trained terrorists have sneaked into these cities to target vital installations. A top Union Home Ministry official today said that Taliban-trained suicide squad have entered the country to carry out attacks at specific installations,including Bhaba Atomic Research Centre, defence establishments Bombay Stock Exchange and RSS headquarters among other likely targets .Instructions have been issued to lay a tightend security net around these installations. He said the police forces have been put on high alert following the inputs and efforts are on to nab the terrorists at the earliest.<br/>