Dehradun: Security has been heightened at public places in Uttarakhand ahead of the Independence Day celebrations, a police official said on Wednesday. While there were no immediate inputs from intelligence agencies of any terrorist movement in the state, the arrest of four Islamic State militant group sympathisers in Roorkie earlier this year had cautioned the security forces here, the official said. The arrested persons had revealed to the National Investigative Agency that rekki for "a certain operation" was undertaken by them at Haridwar, Dehradun and Roorkie, an Intelligence official told IANS. This has alerted the police, intelligence agencies and the security personnel in Uttarakhand and security was beefed up at malls, shopping arcades, bus and railway stations. Security has also been spruced up at government offices and buildings as part of the precautionary measures.