Security checks along the Shenzhen Metro will be extended to more stations and run constantly during operating hours from today to keep dangerous items off trains.
This intensifies security measures that started on March 7, when only a few stations carried out constant checks while others had random procedures.
But all bags will now go through X-ray machines in checks for dangerous fluids, blades and inflammable and explosive materials.
Metro managers warned passengers there may be long queues during peak hours and advised them to add an extra 10 to 20 minutes to traveling times.
The Metro has five lines with 118 stations operated by Shenzhen Metro Group and MTR (Shenzhen). It carries about three million passengers daily.
Staff said that since checks first began many of them for limited periods, such as during major sport events more than 63.75 million passenger bags were screened on lines 1, 2, 3 and 5.
More than 120,000 prohibited items were identified, which led to thousands of confiscations. Nearly 10,000 knives and 20,000 flammable items were also found.
On average, staff added, 836 prohibited items were prevented from being carried into paid areas of stations each day.
Shenzhen police are meanwhile urging people to cooperate and to report any commuters carrying dangerous items.
More officers will also be based around stations to handle confiscated items and deal with uncooperative commuters.
Those who refuse to be checked face being charged under national public security laws.
There have been several incidents at stations in recent months, the most recent being on April 23 at Longhua when a man named Ng cut a staffer at a retail oulet and held two others hostage. Police noted that was not a terrorist attack. JASMINE SIU