'Many commandos and intelligence officials will be in plain clothes and the hotel security staff has already been briefed. The instructions from security agencies have been passed on to them,' the officials said.

The floor on which the US secretary of state will be staying was not revealed to the media, but officials said the floor will be closed from Sunday morning. An access control room will be set up in the hotel to keep up-to-date information.

Arrangements have been made to deploy additional police control room (PCR) vehicles and an ambulance in case of an emergency.

The Delhi Police and Intelligence Bureau are working together on the security issue. US officials have also reviewed the arrangements made.

Security personnel have been deployed along the routes that Clinton will be taking to commute around the city.

She is scheduled to attend a Delhi Climate Change Summit at the ITC Greens Building in Gurgaon and an agriculture event at the Pusa Institute in central Delhi on Sunday. She will visit Delhi University in north Delhi Monday.

Clinton also has several political engagements for Monday, including meetings with Prime Minister Manmohan Singh, Congress president Sonia Gandhi, Bharatiya Janata Party leader L.K. Advani and External Affairs Minister S.M. Krishna. There will be a media interaction too on that day.

Clinton last visited the Indian capital in 2000 when she accompanied her husband, then US president Bill Clinton, and they stayed at the Maurya Sheraton Hotel.

--Indo-Asain News Service