In this photo released by China's Xinhua News Agency, students take an oath not to cheat in the upcoming college entrance exams at Jinling High School in Nanjing, capital of east China's Jiangsu Province, June 4, 2006.

China will scramble mobile phone signals in some exam halls and have police stand guard in a bid to stop cheating as 9.5 million students take the highly competitive college entrance exams this month.

Last year, some 1,700 students across the country were disciplined for cheating, including 30 students who used hidden telecommunications equipment to get answers during the test or who were caught selling exam contents.