National Investigation Agency has registered a case against American terror suspect David Headley and his accomplice Tahawwur Hussain Rana and others in connection with the 26/11 terror attack. The Home Minister Mr. P. Chidambaram said that Headley had visited India several times before 26/11 and once after the attack. Talking to reporters in New Delhi today, Mr. Chidambaram said that inquiries are being made in the cities Headley visited on what he did and whom he met. Mr. Chidambaram said that two more arrests have been made in Pakistan on the inputs of the FBI. In reply to a question, he said that the Indian team which visited Washington recently had good discussions with FBI officials. He said that Indian team did not go to Chicago where Headley is in custody.<br/><br/>Meanwhile, the FBI Chief is visiting in India on 18th of this month in connection with LET terror plot. He will be accompanied by some senior officials of the US investigating agency. During his two day stay in National Capital he will meet top officials of security agencies. He is likely to meet National Security Advisor M K Narayanan.<br/><br/>The security machinery has been put on high alert in the national capital after inputs that suspected LeT operative David Headley might have conducted a recee for carrying out a terror strike. A senior police official said Quick Reaction Teams have been activated and patrolling intensified across the city. Union Home Ministry has already asked five states, including Delhi and Maharashtra, to be on alert. Home Ministry officials say the alerts had been issued as a precautionary measure. It was found during investigations that Headley had visited India nine times during 2006-09. Police is also planning to conduct mock drills to check the preparedness of security agencies in case of terrorist attacks and a security audit of vital installations and other prominent buildings.<br/><br/>In a related move, the Gujarat Police has started investigations following arrest of the suspected terrorist David Headley arrested by FBI in US. According to police sources, Headley had visited Ahmedabad along with some other cities of the country.<br/><br/>As an immediate fall out of the FBI foiling a LeT plot to use US nationals to carry out major terror attacks in India, the Indian Embassy in Washington has tightened visa approval norms for Pakistan-born American citizens.<br/><br/><br/>PTI quoting a top Home Ministry official said that the investigators have enough evidence to show Headley's link with LeT. The official said the Government is all set to produce the documents before the US court in January next and press for their extradition to India. He said New Delhi will press for his extradition to India with these evidences. <br/><br/>Meanwhile, a top Home Ministry official has said that the investigators have enough evidence to show Headley's link with LeT. The official said the Government is all set to produce the documents before the US court in January next and press for his extradition to India.