From Sunday, coach travelers in Shanghai must use their identification cards to buy bus tickets to Beijing. Armed police patrols were added to railway stations to ensure safe transport in the run-up to the Olympic Games.

Shanghai railway police said they had set up a team of nearly 100 Special Police Force officers to patrol Shanghai Railway Station and Shanghai South Railway Station around the clock.

Sniffer dogs would also help beef up security inspections across all the city's transport terminals in the lead-up to the Games, which are due to open on August 8. Shanghai is hosting some Games events, including soccer matches.

"During the Olympics, many of the visiting athletes, judges, accredited crew as well as tourists will be taking trains to the city. That puts great pressure on security," said Lin Ronggui, an officer and news correspondent with the railway police.

Lin said a central office has been set up to coordinate the special rail patrols.

Armed officers and sniffer dogs would be watching out for dubious figures and dangerous goods around station squares and platforms. "We'll also examine all luggage carried on to trains," Lin said.

Shanghai General Long-Distance Bus Station also said it has set up security measures to examine passengers' luggage.

Both city airports will launch security checks at all entrances to airport buildings from next Sunday.

And all roads into Beijing will be under 24-hour police check from next Sunday. Teams of specialists will be checking cars for unauthorized flammable liquids, fuels, weapons and drugs.

Heads of 80 foreign countries will attend the opening ceremony in Beijing on August 8.