A thick security blanket was thrown across the national capital as US President George W Bush [Images], who is on a three-day visit, toured parts of the city, causing major traffic snarls at several places.

Roads leading to the India Gate hexagon and Connaught Place were closed for traffic as Bush traveled to Rashtrapati Bhavan [Images] for a ceremonial welcome and later to Mahatma Gandhi's [Images] samadhi at Rajghat to pay his respects to the Father of the Nation.

The city witnessed huge traffic jams at several places as the Ring Road was closed for vehicles near the Rajghat in the morning.

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Unprecedented security measures are in place in the national capital, particularly in Chanakyapuri and Lutyen's Bungalow Zone areas -- the regions where most of President Bush's engagements are scheduled.

Additional police and paramilitary forces have been deployed in and around the places Bush and his entourage will be visiting, sources said.

US Secret Service agents, camping in Delhi for the last two months, have virtually sealed off the floor in Maurya Sheraton Hotel, where Bush is staying, and have installed hi-tech gadgets to ward off any threat.

Elaborate security checks have been carried out at both the hotels, which have been declared out of bounds for general public.

The Delhi Police have also advised people to avoid the Connaught Place, India Gate areas and the Ramlila Grounds on Friday between 1000 IST and 1600 IST.