Seventy-five suspects involved in recent syringe attacks in Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region, had been detained as of Tuesday, a local police officer said.

"As of Tuesday, police have arrested 75 suspects, cracked seven criminal rings and 36 cases related to the syringe attacks," said Huang Yabo, a senior officer with the regional public security department.

The 36 cases of syringe attacks involved 16 in Urumqi, 13 in Hotan, and two in Turpan, two in Kashgar and one each in the Hui Autonomous Prefectures of Changji, Aksu and Altay.

Huang said that criminologists had been sent to the region to direct investigations.

Three Uygurs were given heavy sentences ranging from seven to 15 years in jail on Sept. 12 for syringe stabbings or threatening to use syringes during robbery.

Hundreds of people have been stabbed by hypodermic syringes or needles in Urumqi during the past three weeks which triggered mass public anger.

Tens of thousands of residents took to the streets earlier this month, demanding security guarantees. Five people died and at least 14 were hospitalized for injuries during the protests.

The city's public security authorities announced earlier this month that police had caught 45 syringe scare suspects.

Tests of victims' samples had found no dangerous viruses or chemicals, medical experts said last week.

Syringe attackers face severe punishment in accordance with the law, including life imprisonment and even death penalties if convicted of causing grave consequences, the city's judicial and police authorities have said.

(Xinhua News Agency September 15, 2009)