Delegates and heads of state of Sri Lanka, Pakistan and Afghanistan, three of the world's most volatile countries, will get extra security during the 14th SAARC summit here from April 3.
"We have decided to tighten security for participants of these countries because of the threat perceptions. Their movements will be closely choreographed," said a senior security official overseeing arrangements.
The summit is expected to see the participation of India, Bangladesh, Pakistan, the Maldives, Sri Lanka, Bhutan, Nepal and new member Afghanistan.
Security will be the tightest for Prime Minister Shaukat Aziz of Pakistan and Presidents Mahinda Rajapakse of Sri Lanka and Hamid Karzai of Afghanistan.
While Islamist terrorists including the Taliban and Al Qaeda are active both in Pakistan and Afghanistan, the Tamil Tigers have dramatically stepped up their campaign against the Sri Lankan state.
Routes from hotels to Vigyan Bhavan, where the South Asian Association for Regional Cooperation (SAARC) summit will take place, will be sanitized and entry of visitors to the hotels will be strictly monitored.
Separate communication networks have been set up in the four hotels where the delegates will stay and they will be connected to the Delhi Police headquarters. No other guest will be allowed to stay on floors occupied by the delegates.
"This is to keep an eye on even the smallest movement inside the hotel premises," said a police officer.
Elite commandos of the National Security Guard (NSG) will assist Delhi Police in carrying out anti-sabotage checks before the arrival of the eight heads of government and state.
Quick reaction teams have also been positioned at hotels and the summit venue to meet any exigency.
The forested ridge area behind the Maurya Sheraton hotel will be barbed and added patrolling has been ordered.
"We will also deploy excess staff at all transit points and security drills would be conducted every day before the arrival of the VIPs," the officer said.
Close circuit television cameras will be put up at all vantage points.
In this year's summit, the US, China, Japan, the European Union and South Korea have been invited for the first time as observers.
Chinese Foreign Minister Li Zhaoxing, Japanese Foreign Minister Taro Aso and South Korean Foreign and Trade Minister Song Min-soon will represent their countries.
The US is likely to be represented by Assistant Secretary of State Richard Boucher and the EU by its New Delhi-based envoy. Observers have been invited to the open plenary and closing meetings.