The suspected leader of a gang that allegedly hired university students to take the national college entrance exam, or gaokao, for its "clients" has been detained by the police in Jiangxi province, authorities said on Monday.

The 48-year-old man, surnamed Zhao, was arrested on a train heading to Jinan, Shandong province, after the test fraud was exposed, according to Jiangxi police.

Jiangxi police also arrested a 20-year-old suspected member of the ring, surnamed Peng, a student at a well-known university in Wuhan, Hubei province.

Police said he confessed and gave the names of five other substitute exam takers.

By Monday evening, nine suspects had been detained by police, according to the Jiangxi Department of Education.

On Sunday morning, police in Jiangxi detained two suspects after the media reported they took the exam under the names of other students.

Southern Metropolis Daily, in Guangdong province, reported on Sina Weibo that one of its reporters had infiltrated a criminal gang that allegedly hired university students to take the two-day national college entrance exam for other candidates.

On Friday, Zhao ordered his assistant to ask four test takers, including Peng, to head to Nanchang from Wuhan to take the test for others, and they were given accommodations in a hotel, according to police.

The police said Zhao gave them fake IDs and the admission cards for the exam, and promised to give them considerable rewards if they obtained a high score, which would help his clients win a place at a top university.

According to the Southern Metropolis Daily reporter, all four test takers were university students from Hubei province, and they had taken the test on previous occasions.

According to Jiangxi police, the suspects usually charged the clients between 40,000 and 50,000 yuan ($8,150) to gain them admission to an undergraduate school. If the test takers helped a student obtain a place at a famous university, the clients were charged more than 1 million yuan.

After investigating the details of the ring and how it operated, the reporter informed Jiangxi police of the test fraud. Its exposure has sparked heated debate among the public and the media.

The provincial educational sector vowed to conduct strict ID checks to ensure the safety and propriety of the exam.

A statement by the Ministry of Education on Monday said the investigation of the test fraud continues and once it is complete, the guilty will be punished and the results will be released in a timely manner.

"We thoroughly investigate illegal behavior during the tests, including organizing others to take the tests for monetary gain," said Xu Mei, an Education Ministry spokeswoman.

The national college entrance exam is regarded as the most important exam for Chinese students.