BEIJING - China has warned its citizens in Algeria about possible attacks from al Qaeda in retribution for a Chinese government crackdown in the Muslim region of Xinjiang.

The Chinese embassy in Algeria on its web site urged all Chinese people and organizations to be more aware of safety precautions and to strengthen security measures in consideration of the situation after the July 5 incident in Urumqi.

The warning came after London risk consultancy Stirling Assynt said in a report to clients that al Qaeda might target Chinese workers in northwest Africa, citing chatter after the July 5 ethnic riots in Urumqi, capital of Xinjiang.

China has been reminding overseas Chinese to pay attention to their safety and enhance self protection ... China will take any necessary measure to protect the safety of Chinese organizations and citizens overseas, Foreign Ministry spokesman Qin Gang told reporters on Tuesday when asked to comment on the report.

Security is heavy in Uighur neighborhoods of Urumqi and other cities in Xinjiang after ethnic riots killed 184 people and wounded more than 1,600. About 1,000 people have been detained.

Two knife-wielding Uighurs were also shot dead by police this week when they attacked another Uighur.

Exiled Uighur organizations said they opposed all forms of violence and condemned the reported al Qaeda threat.

The Uyghur (also spelt Uighur) American Association and the World Uyghur Congress are extremely disturbed by reports that the North African wing of Al Qaeda has threatened to attack Chinese workers in Africa in revenge for the deaths of Uyghurs in East Turkestan, the exiled groups said in an emailed statement.

They said they advocated basic human rights and self-determination for Uighurs, a Turkic people who are largely Muslim and share linguistic and cultural bonds with Central Asia and who now make up less than half the region's population of 20 million.

Chinese workers have been kidnapped, and Chinese convoys attacked, over the past few years in many parts of the world with heavy Chinese investment, including Pakistan and Niger.

(Reporting by Lucy Hornby and Liu Zhen; Editing by Benjamin Kang Lim and Dean Yates)