Beijing's increased subway security to thwart possible terrorist attacks during the Olympics takes effect today.
The municipal government is imposing a series of strict checks on all subway passengers' belongings from now until September 20.
Several days ago, signs asking passengers with luggage to co-operate and a list of prohibited articles were posted at subway station entrances and in passageways leading to platforms.
The main targets of the checks are guns, ammunition, knives, explosives, and radioactive and poisonous substances.
In addition to advanced X-ray surveillance scanners and equipment to check liquids, specially trained police dogs will be deployed to sniff out possible hazards.
It is estimated that more than 3,000 security personnel will be deployed at all subway stations throughout the city.
The news was met with disappointment by some subway passengers.