Centre has alerted all states, to tighten security to foil any possible terror strike. The Home Ministry sources said that the authorities in Maharashtra, Rajasthan, Goa and Delhi have been specifically asked to take extra precautions to guard all places where Pakistani-American terrorist David Coleman Headley had visited and did recce. Security has also been tightened in 36 markets in the national capital by deploying additional 1,200 paramilitary force personnel along with Delhi Police men. Headley, who is currently in the custody of the US, did reconnaissance for Pakistan-based Lashkar-e-Taiba in all places which were targeted on 26/11 terror attacks in Mumbai. He had also recced several key locations in Delhi, Pune and Ajmer.