Attackers with home-made bombs and knives killed 16 police in a restive western region of China today, state media said, in just the sort of violence Beijing had hoped to avoid four days before the Olympics.
The attack, which occurred about 4,000 km from the capital in the old Silk Road city of Kashgar, was a reminder of internal tensions in China, especially in its ethnically mixed and largely Muslim west.
Police said they had information separatists from the East Turkestan Islamic Movement had been planning attacks in the run-up to the Games.
But the organizing committee of the Games said it was sure athletes and spectators would be safe. "We have been preparing the Olympic Games for seven years. We are confident and capable of hosting a peaceful Olympics," said spokesman Sun Weide.
About 100,000 police and soldiers are on standby ahead of Friday's opening ceremony, and security has already been stepped up in Tiananmen Square, scene of pro-democracy protests in 1989, with all visitors' bags being screened.
Police have reportedly identified five terrorist groups in the region who were allegedly plotting to sabotage the Games, according to the state-run Xinhua news agency.
The Xinjiang Uygur Autonomous Region, which has been the heart of China’s security fears, is home to a Sunni Muslim ethnic minority.
Xinjiang's largely Muslim Uighurs have been a focus of China's stringent nationwide security in the run-up to the Games. Officials have said militants seeking an independent "East Turkestan" homeland are among the biggest threats.
One militant group, the Turkistan Islamic Party, pledged in a video that surfaced on the internet last month to “target the most critical points related to the Olympics.”
Many Uighurs resent Chinese controls on religion and of the expanding ethnic Han Chinese presence in Xinjiang, a region rich in natural gas. Some Uighur groups seek an independent homeland, and China has said militants have forged ties with al-Qaeda,
China has said it foiled terrorist plots targeting the Olympics and in the first six months of the year police detained dozens of people in Xinjiang for plotting to sabotage the Games, according to state media.
In March, authorities said they foiled an attempted attack onboard a flight to Beijing from Urumqi, the regional capital of Xinjiang.
Agencies