The organizers of the 2014 Winter Games in Sochi have introduced some of the most extensive identity checks and sweeping security measures ever seen at an international sports event, raising concerns that they are stifling dissent and violating privacy under the pretext of fulfilling their pledge to make the games "the safest Olympics in history."

With an Islamist insurgency raging across the North Caucasus Mountains east of the Black Sea resort, Russia s security agencies have had carte blanche to ensure that nothing spoils President Vladimir Putin s pet project. While the official line is that the stringent measures are meant to block the terror threat, critics say the Kremlin is equally concerned about preventing anti-Putin protesters from raising an embarrassing ruckus at the games.

The filters are activated right at the ticket-buying stage.

Anyone wanting to attend the games that open on Feb. 7 will have to buy a ticket online from the organizers and obtain a "spectator pass" for access. Doing so will require providing passport details and contacts that will allow the authorities to screen all visitors and check their identities upon arrival. Guests will be asked to wear their passes while attending Olympic events for quick and easy identification.

Russian government officials and Sochi organizers say the security pass is necessary to keep the games safe. Some critics, however, says that it will do little to deflect a terror threat from people already in the Sochi area, as potential terrorists would have had years to settle within the security zone.

"This kind of pass, this kind of measure might stop some people from going to the Olympics ... but this kind of measure can t deal with the people who actually live in the area," said Andrei Soldatov, an independent Moscow-based security analyst.

While China was criticized for undeclared visa bans on people from some countries in the Middle East and Africa during the 2008 Summer Games in Beijing, it introduced identity checks only for the opening and closing ceremonies.

Organizers of the 2012 London Olympics put up some unprecedented security, including patrols by combat jets, surface-to-air missiles on rooftops and an aircraft carrier on the River Thames, but they didn t reqire any passes in addition to tickets.

The tens of thousands of police, security agents and army troops to be deployed in Sochi are twice as many as during the London Summer Games, said Matthew Clements, an analyst at Jane s.

"The Sochi security effort is much more far-reaching," Clements said. "This also represents the fact that there is an active insurgency operating in the near vicinity."

Militants aspiring to create an Islamic state in the North Caucasus have spread across the region after two separatist wars in Chechnya. The epicenter of the rebellion is in the Caspian Sea province of Dagestan, about 500 kilometers (300 miles) east of Sochi, where rebels launch near daily attacks on police and officials. But other Caucasus provinces lying closer to Sochi also have been roiled by violence.

Clements said that the security zone created around Sochi stretches approximately 100 kilometers (60 miles) along the Black Sea coast and up to 40 kilometers inland. Russian forces include special troops equipped for patrolling the forested mountains towering over the resort, speed boats to patrol the coast and state-of-the art sonars to spot submarines.

The security regime includes a ban on the entry of all cars from outside the zone starting one month before the games and ending only one month after they end. Vehicles involved in servicing the Olympics but registered elsewhere need special passes.

Inside the Sochi security zone, the government has a list of more than 600 facilities to be put under special protection months before the games. Along with the Olympic facilities, bridges, railway tunnels and depots, the list includes Sochi schools, kindergartens, hospitals, hotels, restaurants and stores.

Russian security agencies have developed a massive surveillance system that critics say will allow them to intercept any phone calls and Internet traffic, with a particular emphasis on Sochi.

Russia s communications surveillance system, SORM, the Russian acronym for the System of Operative Investigative Measures, has required all telecom providers to install equipment that feeds all traffic directly to security agencies.

Their officers are required by law to have a court sanction for eavesdropping, but they don t have to show it to anyone.
"The system ... is very intrusive," Soldatov said, "much more intrusive than in the West."

Official papers have suggested that the SORM system in Sochi has been modernized to cope with the heavy flow of communications during the games, but officials have said little about the details.

Earlier this year, the Communications Ministry issued a directive urging all communications companies to introduce new equipment capable of intercepting mail traffic on Gmail and Yahoo.

Soldatov said that in addition to terrorists, authorities may be looking to filter out protesters.

A controversial Russian law banning gay "propaganda" has drawn broad international criticism, and activists may be planning protests in Sochi despite an official ban on all rallies.

The Russian government also has invested heavily into other means of surveillance, installing some 5,500 closed-circuit cameras throughout Sochi and buying a fleet of drones. The drones could be particularly handy for quickly spotting anyone attempting to break an official ban on protest in Sochi.

Months before the games, security agencies have moved to expel some of those whom they consider unwelcome. In particular, police have conducted sweeping document checks among thousands of migrant workers who were recruited to build Olympic facilities and deported many, drawing criticism from rights groups.

Critics compared the measures to the Soviet actions ahead of the 1980 Summer Games in Moscow, when the KGB simply sent all those deemed suspicious out of the capital.

Police in Sochi have conducted methodical house-to-house checks to screen residents and advised those who lack permanent registration in the city to leave.

Police and other security agencies have run dozens of drills to prepare for possible emergencies. The latest involved several dozen people posing as terrorists to check the readiness of security agencies and the vigilance of the population. The exercises also involved checking all cars at entry points to the area, exasperating motorists who spent hours in traffic jams.