With 15 million visitors including heads of state due to visit the World Exposition, host Japan will try to ease safety concerns through a display in its own right -- security robots.
The expo, whose exhibits range from a frozen mammoth dug up in Siberia to humanoid robots, opens to the public on Friday with guests to include Japanese Emperor Akihito and Prime Minister Junichiro Koizumi, French President Jacques Chirac, Australian Prime Minister John Howard and Central American leaders.
The six-month expo, which traces its history to the 1851 Great Exhibition in London, aims to show the cutting edge in technology and innovation with 121 countries setting up displays in a forest park in central Aichi prefecture.
As many as 3,000 police will join some 1,000 private guards at the venue -- along with eight security robots who will guide visitors by day and patrol by night.
"This is the first World Expo in which measures against terrorist attacks are top priority," said Toshio Nakamura, secretary-general of the Japan Association for the 2005 World Exposition.
Special police squads to handle bombs and chemical weapons will be on stand-by with gas masks and explosive disposal equipment.
"After the Iraq war, we decided to put emphasis on measures against terrorism," said Yuichi Yokoyama, vice chief of the exposition security office of the Aichi police department. "We especially beefed up security at pavilions of countries involved in the war such as the US, Britain, Japan."
The robots also offer an opportunity to show off Japanese technology.
"It's a great chance to display the potential for the use of robots for the purpose of security," said Daisaku Sudo, an official of Japanese robot maker Tmsuk Co Ltd.
Ligurio, a prototype security robot produced by the company, can move at a maximum speed of 7km per hour and recognize a stranger 50m away even at night, using microwave sensors.
The ?60 million (US$573,000) robot is equipped with a voice warning system and two folded arms that can grab explosives or lethal chemical containers and remove them to safe places.
In a demonstration, the 150cm robot with a barrel-shaped body and two headlights like eyes removed a fake explosive, saying: "A dangerous object was found. It will be removed."
"A robot can be fixed or reproduced when it's broken on duty, but human beings cannot have replacement," Sudo said.
Guard Robo i, another security robot produced by Sohgo Security Service Co Ltd, a Japanese firm, can follow strangers and shoot paint bullets at them.
The company said the image of a robot on guard could become increasingly common, as Japan is one of the world's most aging societies with a potential labor shortage looming.