A suspect who used a needle-like item to prick people in Chang'an district of this capital city of northwest Shaanxi province was detained on Sunday by police.

The detention came after several needle attacks had been reported to local police since late last month. The needle attacks in Xi'an followed similar attacks in the Xinjiang Uygur autonomous region.

The suspect, Wang Xing, 26, a male villager in Liucun village of Chang'an district, pricked a female college student's back with a needle-like bamboo stick on Sept 12 in a downtown street of the district, said Liu Liju, a police officer with the publicity section of Chang'an district public security bureau, in an interview with China Daily.

"The suspect confessed his criminal acts and we requested approval from the municipal procuratorate to arrest the suspect on Tuesday," Liu said.

The student suffered a minor injury and is doing fine now, police said.

Several needle attacks have been reported since late last month, said Qian Baiyun, director of the publicity department of Xi'an public security bureau.

His bureau has sent more than 2,400 policemen to patrol downtown areas around the clock to keep public order and search for any potential criminals.

Starting Sept 13, every bus in the city will be checked by policemen with police dogs before it begins operation every morning. More than 5,000 plain-clothes police and security staff will be on duty on every bus to guard its safety, Qian said.

Local police also announced that they will crack down on the needle attacks, which are considered a serious criminal activity, according to the law.

The police said in a statement that those who have carried out needle attacks should give themselves up to police as soon as possible. Those who do will receive a reduction in or exemption from punishment if they report and expose other attackers.

Those who received the needle-like pricks are showing no obvious trauma or any other complications, the police said.

Ma Zhonglin, deputy director of Xi'an public security bureau, said that his bureau had taken strict measures to ensure social order and has worked hard to track down criminals as soon as possible.

"And we should remind local residents to heighten their vigilance and strengthen their own security precautions. But they should remain calm and report to police when they find any suspects," Ma said.

Wu Kejun, a local resident, said that he did not think the so-called needle attacks would destroy public order. Most people believe the police will keep good public order in the city.

Xi'an municipal public security bureau has set up a special police hotline for the needle attacks and promised to reward those who provide clues and information to crack the cases or catch the suspects.

In order to keep order to usher in the coming National Day holiday from Oct 1 to 8, the Xi'an police bureau put some 14,000 policemen into a high state of alert and organized more than 38,000 militias, security volunteers and information staff to guard shops and markets, communities and schools.