Commonwealth Games venues and Athletes Village will have a complete lockdown from midnight tonight with entry to be allowed only to those carrying valid passes.
A large number of armed policemen, including paramilitary personnel, have been deployed across the stadia and village. Sophisticated gadgets have also been installed at the stadia.
"The lockdown will start from this midnight," a senior police official said.
The security has been stepped up across the city after Sunday's firing incident at Jama Masjid that injured two Taiwanese nationals.
Delhi police, which is the nodal agency for Games security, have conducted various drills, including anti-sabotage checks once they take over possession of the venues, the official said.
Apart from around 80,000 Delhi police personnel, over 17,500 paramilitary personnel, 3,000 commandos and 100 anti-sabotage check teams will be deployed across the city.
The army has been asked to be alert.
Concerns were earlier raised about the delay in handing over venues to security agencies as some quarters felt that it would hamper the security preparations.
Delhi police commissioner YS Dadwal, however, had downplayed the delay and said the force was prepared to handle the security issues related to the sporting extravaganza.
"We know the stadia and surrounding areas. We know the city very well. So securing them or other areas will not be a problem," Dadwal had said when asked whether the delay in completion of Games projects was compromising security preparedness.
Union home minister P Chidambaram also reviewed the arrangements.
Heli-borne snipers, four-layered security cordon around Commonwealth Games venues and exclusive lanes for Games vehicles were among the components of the mammoth security plan for the event.
The security plan prepared for the mega event, which will see participation of around 8,500 athletes from 71 countries competing in 17 events, also envisages snipers on rooftops, commando hit teams and expert groups to tackle any chemical, biological, radio-active or nuclear attacks.
Air Force will provide surveillance from the skies. Heli-borne assault teams will also be deployed to thwart any terror strikes.
"We are closely working with central intelligence agencies. The air force will be surveying the airspace. We will have heli-borne snipers patrolling the skies," the official said.
According to the plan, the venues, Games Village, practice and parking lots and the Indira Gandhi International Airport where athletes arrive will have a four-layered security cordon.
At the outer cordon, the traffic will be stopped and access controlled. At the middle cordon, security-men will channelise the spectators to their designated seats while in the inner cordon, barcode reading of tickets will take place and spectators' photographs taken.
At the centre would be an exclusion zone which is in the 30m radius of the stadium, where spectators and others will have to go through door-frame metal detectors and X-ray scanning besides manual searching.
Mobile quick reaction teams (QRT) will be deployed on the outer perimeter of the venues besides a close watch through CCTV surveillance.
The Games Village will also have a similar elaborate security arrangement. The boundary of the village will have a 3m high perimeter wall, a 1.5m-high iron grill on top of it, mobile QRTs and CCTV surveillance system.
Elaborate arrangements are also made for the entry for athletes and vehicles into the village. After entering the village following a thorough check, the athletes can freely move around the residential and dining halls.
For vehicles, the drivers will have to pass through radio frequency identity checking where the number plates are checked to see whether are authorised to enter the place.
There is a boom barrier and it will be opened only after the vehicle clears the radio frequency checking. But if somebody tries to forcefully enter, there will be a tyre-killer and even if the vehicle clears it, the road blocker will block the passage of the vehicle.
At the hotels, there will be "robust" security arrangements with watch towers, CCTV surveillance and access control.
"All food prepared and served for Games guests in hotels will be sorted by security personnel and tasted by food experts," the official said.
With large number of athletes, officials and tourists reaching the city for the Games, security at and around the Indira Gandhi International Airport is also being augmented.