FACTBOX: Fortress Beijing: Security steps for the Olympics

(Reuters) - China, which says it has already cracked domestic terror plots targeting the Olympics, has taken sweeping steps to secure the Games against protests or attacks.

By relying on its armed forces Beijing hopes to pay less than a third of $1.8 billion previous-host Athens paid for security.

Here are some facts about security at the August 8-24 Games.

SCREENING VISITORS

-- Visa rules have tightened. Travelers must now show a return air ticket and a hotel booking before buying a visa.

-- Hong Kong, host of Olympic equestrian events and a major gateway to China, has created a watchlist of unwelcome activists, and brought in new visa restrictions ahead of the Games.

-- Interpol is to give Beijing airport and other major border entry points access to its database of more than 14 million lost or stolen travel documents.

SECURITY CAPABILITIES

-- A 100,000-strong security force, including the elite Snow Wolf Commando Unit, is already on alert for terrorists.

-- 300,000 surveillance cameras watch the city.

-- Since May, the team of People's Liberation Army (PLA) engineers in charge of Games security checks and emergency rescues has run daily drills on finding and defusing explosives, rescuing and evacuating people from damaged buildings.

-- The United Nations nuclear watchdog has trained Chinese security personnel to respond to radiological attacks -- such as a "dirty bomb" -- in which radioactive material is released.

OLYMPIC VENUES

-- At least two surface-to-air missile launchers were set up in late June about a kilometer south of the Bird's Nest National Stadium.

-- Authorities pledged to revamp public emergency shelters by the venues last October, saying 20 to 30 new shelters, with room for 1.5 million to 2 million people, were needed every year.

-- Gas stations within 300 meters of Olympic venues and all Games-designated gas stations must install video surveillance equipment and "explosion-prevention devices".