Beijing passengers will have to face security checks by machines, dogs or police officers at all subway stations as from the end of June.

Friday's Beijing Morning Post quoted the city's public security bureau as saying that security measures would cover all operational subway lines and Line 10, which is yet to go into operation.

The capital has a very busy subway system. On April 30, it carried 4.3 million passengers daily, breaking its own record. But no security equipment has been installed at subway entries except Dongzhimen station in eastern Beijing along Line 2.

Passengers will have to drink bottled water and other beverages they carry into the subway if security machines and police dogs could not identify them, the police source said.

The police called on passengers to cooperate, the newspaper said. It also publicized a hotline 008610-64011327 for information on people bringing combustible substances and explosives into the subway.

The city police will also install security machines at busy bus stations.

A bus fire that claimed three lives in Shanghai was caused by flammable oil-like material carried on board by a passenger, according to local police.

Passengers are banned from carrying dangerous substances on board public transport, including buses, subways, trains and aircraft, and offenders can be jailed for five to 15 days.

In the first four months of this year, the Beijing police had caught 44 offenders, but they did not cause accidents.