Beijing  - China's capital has begun tightening security before major events to mark the 60th anniversary of the People's Republic of China on October 1, state media said on Monday.

New measures include the reactivation of a traffic security cordon used as an anti-terrorism measure during last year's Olympic Games in Beijing, the official Xinhua news agency said.

Police checkpoints began operation on all major roads into Beijing over the weekend, the agency quoted public security officials as saying.

Thousands of paramilitary officers are guarding bridges, railways, road tunnels and other important infrastructure sites in Beijing, it said.

Security is also tighter on Beijing's subway system and near the city's Tiananmen Square, which will host the main celebration of the founding of the People's Republic of China in 1949.

Tiananmen Square was also the focus of student-led protests which the ruling Communist Party ended with a bloody military crackdown in June 1989.

The government increased surveillance of dissidents before the 20th anniversary of the crackdown and is expected to continue to keep many activists under house arrest or close monitoring until after the October 1 celebrations.

At least 7,000 police officers are patrolling the city's streets each day, while public security officials are trying to recurit some 800,000 volunteers to "watch for suspicious strangers around their communities," the agency said.

Unlike last year's Olympics, potential terrorist threats to the National Day celebrations are "more likely to come from inside the country than from abroad," it quoted Beijing police official Wang Jun as saying. (dpa)