BEIJING (AFP) — Eight people died in bombings and fierce clashes between police and attackers in China's remote northwest Sunday, state media reported, the second outbreak of deadly violence there in under a week.

Soldiers were called in to secure the city of Kuqa in Xinjiang, a Muslim-populated region home to what China says are Islamic terrorists intent on turning the nation's Olympic celebrations into mourning.

Chinese authorities did not identify who the attackers were in Sunday's assault, but said they targetted police and government offices, and that some of them killed themselves when confronted by security forces.

Seven of the attackers died in the violence, while one security guard was killed, the official Xinhua news agency reported.

The clashes began with assailants setting off an explosion at Kuqa police station, with that blast killing the security guard as well as injuring two policemen and two civilians, according to Xinhua.

Five "bombers" were found hiding in a market a few hours later. Police shot two of them dead as the attackers threw home-made explosives. Three of the attackers "blew themselves up," Xinhua reported without elaborating.

There were at least 15 attackers involved in the day's violence in total, and 12 gas-based pipe bombs exploded in all, it said.

Local authorities refused to comment when contacted by AFP, but a resident confirmed Xinhua's report that the military and police had quickly locked down the centre of Kuqa, a city of 400,000 people.

"Don't come today, the town centre is closed," a receptionist at the Kuqa Hotel told AFP by phone.

It was the second deadly assault in less than a week in Xinjiang, a vast area that borders central Asia.

Two alleged Muslim militants using explosives and knives attacked policemen out jogging in the Xinjiang city of Kashgar on August 4, leaving 16 dead and 16 wounded.

China blamed that attack, which occurred four days before the start of the Beijing Olympics, on Islamic militant Uighur separatists.

Xinjiang has about 8.3 million ethnic Muslim Uighurs, many of whom express anger at what they say have been decades of repressive Communist Chinese rule.

Two short-lived East Turkestan republics emerged in Xinjiang in the 1930s and 1940s, when Chinese central government control was weakened by civil war and Japanese invasion.

China has repeatedly accused Uighur militants of the banned East Turkestan Islamic Movement of plotting attacks on the Olympics and has implemented sweeping security in Xinjiang and in Beijing in the lead-up to the Games.

"We can see clearly that these forces are trying to wage a psychological and violent battle against the Olympics," said Shi Dagang, Communist Party secretary of Kashgar, last week following the attack there.

"They want to turn the year 2008 into a year of mourning for China."

Uighur separatists in Xinjiang have also released two video statements threatening to attack the Olympics.

But Olympic organisers sought to reassure the hundreds of thousands of foreigners in China to attend the Games that Sunday's attack should be of no concern for them.

"I do not believe this will have an impact on the Olympic Games... I do not think it is related to the Olympics," Wang Wei, vice president of the organising committee for the Games, told reporters in Beijing.

He emphasised that security had already been stepped up in Xinjiang.

Kuqa is about 740 kilometres (460 miles) from Urumqi, the regional capital of Xinjiang, and more than 3,000 kilometres from Beijing.