Olympic terror fears as grenade blast kills 16 police in China just four days before opening ceremony

Just four days before the Games are due to open in China's capital, two attackers drove up to a police base in a rubbish truck, throwing grenades before setting on injured officers with knives.

The attack is believed to have been carried out by a terror group that has threatened to strike at the Olympics and is said by the Chinese authorities to have links to Al Qaeda.

Chinese paramilitary police patrol the airport in Urumqi, the capital of China's far northwestern, mainly Muslim Xinjiang region today.

After the truck hit an electrical pole, two attackers jumped out, threw two grenades at the barracks and "also hacked the policemen with knives," witnesses said.  Two of the policemen died on the way to hospital, the rest died at the scene.

The ambush took place at a border post in Xinjiang province in north-west China where local Muslims have waged a sporadic rebellion against Chinese rule. The two attackers, one injured, are said to have been captured near the city of Kashgar.

The police officers were reported to have been jogging outside their post when the attack - the latest in a series of successful high profile strikes by separatists in the region - happened.

The head of Beijing's Olympic security, Colonel Tian Yixiang warned last week that fundamentalists from the radical Turkestan Islamic Party in the region posed the greatest threat to the Games.

In a video entitled "Our Blessed Jihad", the group's head, Commander Seyfullah, said it was responsible for a series of recent attacks on civilians and security forces and said the Olympics were its target.

"The Chinese have haughtily ignored our warnings," he said, "The Turkestan Islamic volunteers...have started urgent actions," adding it would "target the most critical points related to the Olympics."

The group is believed to be based across the border in Pakistan, with some of its core members having received training from Al Qaeda and the Pakistani Taliban, according to terrorism experts.

A local Turkic Muslim people, the Uighurs, have chafed under Chinese rule, fully imposed after the communists took power nearly 60 years ago. Occasionally violent attacks in the 1990s brought an intense response from Beijing, which has stationed crack paramilitary units in the area and clamped down on unregistered mosques and religious schools that officials said were inciting militant action.

Separatist groups have been linked to two attacks on buses last month in Yunnan and Shanghai that left five people dead.

In recent months police claimed to have foiled a plot to explode a Chinese passenger plane and plans by terrorist cells to kidnap athletes, journalists and others involved in the Olympics.

Last month the authorities said they had arrested 82 people targeting the Olympics and said they had broken up five groups with links to Uighurs who posed a threat to the Games.

Human Rights groups say Beijing's leaders have used Olympic security as an excuse to crackdown on the Uighurs.

Terrorism experts and Chinese authorities, however, have said that with more than 100,000 soldiers and police guarding Beijing and other Olympic co-host cities, terrorists were more likely to attack less-protected areas.

Beijing was yesterday a gridlock of checkpoints as spot checks were carried out and police patrolled all major roads leading to the Olympic venues.

A small group of protesters who clashed with police near Tiananmen Square, saying the happiness of the Beijing Olympics was built on their pain, were swiftly led away.

The protesters said they had been evicted from their homes to make way for reconstruction of the district. The area is being rebuilt into a commercial strip with businesses such as Nike, Starbucks and Rolex.

Demonstrations in and near central Beijing's Tiananmen Square are rare and generally stopped quickly by police. China is sensitive to any public criticism of the Olympics, and has stationed security agents throughout the city to watch for signs of unrest.

One of the biggest problems facing the authorities remains pollution with a heavy, thick haze returning to hang low over Beijing after three clear sunny days.
China said it will begin monitoring additional air pollutants after the Olympic Games as part of efforts to expand pollution controls.

The Environment Ministry releases an air pollution rating each day for Beijing, called
an Air Pollution Index, but this does not include ozone and tiny particulate matter.

The ultra-fine dust particles, at 2.5 micrometers, are considered especially harmful to health because they are small enough to penetrate the lungs and create respiratory problems. Ozone, a colourless gas, can also cause respiratory problems.

The host city's polluted air has been one of the biggest worries for Olympic organisers and prompted drastic measures earlier this month that included pulling half the city's 3.3 million vehicles off the roads, halting most construction and closing some factories in the capital and surrounding provinces.