Sixteen Chinese policemen have been killed in an attack on a border post in the restive Muslim region of Xinjiang, state media say.
Two attackers reportedly drove up to the post in a rubbish truck and threw two grenades, before moving in to attack the policemen with knives, reported BBC.
The attack came four days before the opening ceremony of the Olympic Games.
Both attackers were captured during the raid near the city of Kashgar, Xinhua news agency reported.
Xinhua said the attack happened at about 0800 (0000 GMT).
Fourteen policemen died at the scene and two on the way to hospital. Another 16 of the policemen were injured.
One of the attackers received a leg injury.
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.
Last week, a senior Chinese army officer warned that Islamic separatists were the biggest threat to the Olympics.
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."