Police in Beijing are clamping down on security throughout the city's subway system, media sources report.

According to Hindu.com [1]:

The security checks will be carried out by machines, sniffer dogs or police officers from June end, state media said.

The busy Beijing subway system which carries about 4.3 million passengers daily does not have any security equipment installed at entries so far, barring Dongzhimen station in eastern Beijing.

New security measures would cover all operational subway lines and Line 10 which is yet to be put into operation, official Xinhua news agency said quoting a Beijing Morning Post report. It did not however link it to Olympics.

Xinhua also reports [2]that security machines will be installed at the city's bus stations. Early last week, a bus fire left three people dead when a passenger brought a flammable liquid on board a city bus. Passengers are forbidden to carry dangerous substances throughout the city's mass transportation system. Violators can be jailed for five to fifteen days, according to Xinhua.