New Delhi, Jan 26 (ANI): The national capital turned into a fortress as US President is all set to witness the 66th Republic Day parade on Monday. There is unprecedented security in New Delhi. A seven-layer security ring with 50,000 security personnel, including 500 US Secret Service Agents, are part of President Obama's security detail. Police personnel are keeping a tight vigil throughout the national capital and also around the area where the parade is to take place since last night. Meanwhile, Prime Minister Narendra Modi also took to twitter to congratulate and give greetings to the nation on 66th Republic Day. The highlight of this year's parade will be the indigenously developed surface-to-air Akash medium range missiles and weapon locating radar. The long-range advanced MiG-29K fighter will be seen for the first time. Three all-women marching contingents of the Army, Navy and the Air Force will represent the theme of the parade, "Nari Shakti (woman power)".