Students leave examination site after attending the first subject test of college entrance exam, or Gaokao, at a middle school in Qingdao, east China's Shangdong Province, June 7, 2010. About 9.57 million examinees in China attend this year's national college entrance exam, which is held from June 7 to 8. (Xinhua/Li Ziheng)Police and education authorities have stepped up security at exam venues across China to ensure safety and curb cheating, as more than 9.57 million Chinese high school students Monday began sitting the three-day national college entrance exam.

At most venues across China, metal detectors are used to prevent candidates from taking any electronic device into the exam, including watches. Clocks are installed on the walls of the classrooms to inform test-takers of the time.

Surveillance cameras are installed in nearly 110,000 exam venues in 25 provinces so that central and provincial education authorities can simultaneously oversee different venues from a distance, according to a statement from the Ministry of Education.

In northeast China's Jilin Province, where a cheating scandal ignited national outcry last year, more than 3,000 police have been dispatched to the exam venues for 160,000 candidates, said Vice Governor Chen Xiaoguang.

More than 1,200 disciplinary inspectors are patrolling the venues, which are monitored by surveillance cameras, he added.

Troops are mobilized to ensure security in transporting the test papers to 6,800 venues in northwest China's vast Xinjiang, said deputy government head Jin Nuo.

Most of the venues in Xinjiang, where 164,500 students are taking the exam, are installed with surveillance cameras, she added.

Central China's Henan, the only province to have a population of more than 100 million, has over 950,000 examinees, said Vice Governor Xu Jichao.

Henan's police have launched round-the-clock checks on the Internet for the online selling of cheating devices and exam-related scams.