Air, rail and long-distance bus facilities in Beijing are on heightened alert as the Olympic Games approach.

Armed police with dogs began round the clock patrols on Monday at the capital's four railway stations, including a new one in the southern district that hasn't yet opened.

At the Beijing West Railway Station, a major terminal, passengers are asked to taste any liquids they carry or put a sealed one under a special detector handset to identify its contents.

"The detector will show if the liquid is alcohol or gasoline," said a police officer in charge of the security check.

At each entrance to the station, six officers carry out security checks. And at baggage facilities, every piece of left baggage must be X-rayed and banned substances like banana oil and paint must be taken out.

All checked luggage would also be X-rayed and checked by police dogs, according to the railway police.

From Sunday, Beijing International Airport started security checks at every entry against explosives.

Security staff swipe large items with indicator paper, which is then put into a machine that can detect explosive residue. Passengers must open small carry-on items for inspection.

Police dogs are playing a key role, with dozens on patrol in terminals. Each dog will rest for about half an hour after two to three hours of work, according to the airport police.

"The security check did cause some delays. So we changed the strategy a bit," said Zhang Zhi, deputy head of the airport police. Those without luggage, who did not show any suspect behavior, were allowed in the terminal buildings without checks, he said.

During busy periods, police dogs are at entrances to help with security checks and passengers only carrying small hand baggage are allowed in without inspections.

Most passengers expressed understanding. "I was at the airport one hour earlier than usual after learning about these security measures," said a passenger surnamed Pan.

Li Lei, an airport official in charge of terminal management, suggested that passengers arrive two and a half hours before departure to avoid delay.

Beijing's 10 long-distance bus stations adopted security checks on passengers as of Sunday. The police found 53 cases of banned substances, including alcohol and ethane, so far.

(Xinhua News Agency July 22, 2008)