Security at two of?rail depots in Shanghai has been tightened ahead of next month's military parade in Beijing in a bid to stop anyone from tampering with trains bound for the capital, police said yesterday.

The Baoshan Road and Guangxin Road depots near Shanghai Railway Station are being guarded around the clock, said Zeng Jian, a railway police officer based near the two sites.

"This is a temporary measure to prevent undesirables from trying to smuggle dangerous items onto the trains that serve Beijing," he said.

A military parade to commemorate the end of World War II and the War of Resistance Against Japanese Aggression is scheduled to be held in Beijing on September 3.

Police officer Lin Ronggui said the extra security was necessary as there have been cases in the past of people secreting items onto trains parked at depots or even bribing train guards to carry things on their behalf.

"The aim of the increased security is to eliminate risks before they are allowed to happen, before passengers get on the trains," he said.

Despite the increased police presence at the rail depots, Lin said that passengers are unlikely to notice any real changes to the security situation at railway stations.

"We have asked security guards to check luggage items carefully, but there will be no significant increase in the security procedures for people traveling to Beijing," he said.