Beijing (PTI): Passengers at all subway stations would be subjected to security checks from the end of June, as police here is ramping up safety measures ahead of the Olympics.

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.

The Police have also publicised a hotline for information on people bringing combustible substances and explosives into the subway, it said.

Three persons were killed in a bus fire in China's economic hub, Shanghai, early this week, with police saying it was caused by flammable oil-like material carried on board by a passenger.

Beijing Police have also tightened security at China's political symbol Tiananmen square, from where the establishment of Communist China was proclaimed in 1949, by clamping more regulations.

"Security around Tiananmen is very important and has great international influence, Zhang Peili, a Beijing legal official was quoted as saying by Xinhua earlier.