BEIJING (AP) — The western Chinese region shaken by ethnic rioting and needle (syringe) attacks is tightening controls over the sale of dangerous chemicals in an effort to improve public safety, state media reported Tuesday.

Individuals or companies in Xinjiang wishing to buy dangerous chemicals will have to register with an identification card or business license, the Xinhua News Agency said. Purchases of even more toxic chemicals will require certificates of permission from their local police, Xinhua said.

The order comes amid tensions in the region's capital, Urumqi, after violence in July between members the native Uighur ethnic group and China's majority Han that left 197 dead. A recent series of needle attacks sparked street protests last week in which authorities say five were killed.

Hoping to ease public anger, Beijing removed Urumqi's Communist Party boss and Xinjiang's police chief on Saturday. Authorities in Urumqi ended an overnight curfew Tuesday morning but vowed to maintain calm.

Tuesday's Xinhua report did not list the restricted chemicals by name, although the order appeared directed at controlling caustic or potentially explosive substances that could be used in terrorist attacks. Xinjiang has long been home to a low-frequency Uighur separatist insurgency.

The report said chemical dealers must be licensed and keep detailed records of all sales, including the intended uses.

The government has blamed the rioting and the needle attacks on the separatists.

In a public notice late Monday, Xinjiang's Public Security Department said police received 77 reports of new needle attacks between 5 p.m. Sunday and 5 p.m. Monday in Urumqi. Previously, about 530 people had reported attacks, but only about 100 showed physical signs such as scratches or puncture wounds.

The government has vowed harsh punishment for those who committed the attacks, including sentences of 3 years to life in prison or even the death penalty. Those who falsely report needle attacks to cause public fear will also face punishment.

Authorities also announced that a building built by and named after Rebiya Kadeer, a Uighur dissident blamed by the government for stoking ethnic tensions, will be demolished. Kadeer had been a prominent businesswoman before she was exiled to the U.S.

Xinhua said the building, with more than 500 stores on four floors, has fire and safety issues and must be torn down.

Other older buildings in the area will also be demolished, Xinhua said.