Chinese border assault kills 16 The attack is believed to be one of the bloodiest in Xinjiang's history Sixteen Chinese policemen have been killed in an attack on a border post near Kashgar city in the western region of Xinjiang, state media say. Two men drove a lorry into a group of jogging policemen before attacking them with explosives and knives, according to the Xinhua news agency. Police say both attackers - ethnic Uighur Muslims - have been arrested. China has warned that militant Uighur separatists may target the Beijing Olympic Games, which start this Friday. Kashgar, known as Kashi in Chinese, is some 2,500 miles (4,000km) from Beijing, near the border with Tajikistan. Xinhua said the attack happened at about 0800 local time (0000 GMT), as the policemen were jogging outside the compound. How big is the Xinjiang threat? Q&A: China's Uighur problem Fourteen policemen died at the scene and two on the way to hospital. Another 16 policemen were hurt. One of the attackers was reported to have been injured in the leg. Xinjiang, in the north-west of the country, is home to the Muslim Uighur people. Uighur separatists have waged a low-level campaign against Chinese rule for decades. Human rights groups say Beijing is suppressing the rights of Uighurs. The BBC's Daniel Griffiths in Beijing says China has spoken in the past of what it calls a terrorist threat from Muslim militants in Xinjiang, but it has provided little evidence to back up its claims. A spokesman for the Beijing Games Organising Committee told Xinhua he was confident that Olympic participants and spectators would be safe. "China has focused on strengthening security and protection around Olympic venues and at the Olympics Village, so Beijing is already prepared to respond to any threat," Sun Weide was quoted as saying. Warnings Last week, a senior Chinese army officer warned that Islamist separatists were the biggest danger to the Olympics. CHINA'S UIGHURS Ethnically Turkic Muslims, mainly in Xinjiang Made bid for independent state in 1940s Sporadic violence in Xinjiang since 1991 Concerned about Chinese immigration and erosion of traditional culture Col Tian Yixiang, of the Olympics security command centre, told reporters the main threat came from the "East Turkestan terrorist organisation". The term is used by the government to refer to Islamist separatists in Xinjiang. Late last month, a group called the Turkestan Islamic Party said it had blown up buses in Shanghai and Yunnan, killing five people. But China denied that the explosions were acts of terrorism. The Washington-based IntelCenter, which monitors terrorism communications, said the Turkestan Islamic Party had released a video entitled Our Blessed Jihad in Yunnan. In it, the group's leader, Commander Seyfullah, said it was responsible for several attacks and threatened the Olympics. "The Chinese have haughtily ignored our warnings," IntelCenter quoted him as saying. "The Turkestan Islamic Party volunteers... have started urgent actions." 'Evicted' In Beijing, Chinese police and a small group of protesters clashed in Qianmen district, near Tiananmen Square. The demonstrators complained that they had been evicted from their homes to make way for the reconstruction of the district. The Olympic torch is due to be carried round a stadium in Mianyang, Sichuan province, which was used to house thousands of people forced from their homes by a devastating earthquake in May. The torch will go on to the provincial capital in Chengdu on Tuesday before heading to Beijing for the opening ceremony on Friday.