Authorities in China's restive Xinjiang region have issued a "most wanted" list and offered rewards for tipoffs, a government website said Wednesday, continuing the forceful official response to recent unrest ahead of a sensitive anniversary.

After two violent incidents left at least 35 people dead last week, China has boosted security in the regional capital Urumqi while top officials and state media have vowed to crack down on such "terrorist" attacks.

"We hope more people will help us with information and leave terrorists with no place to hide," the Xinjiang official news website Tianshannet quoted senior police information official Li Li as saying.

But overseas rights groups say the unrest stems from discrimination against ethnic minority Uighurs in Xinjiang, a far-west desert region which has seen an influx of majority Han Chinese in recent years.

Some of Xinjiang's worst violence in years erupted on July 5, 2009, when around 200 people were killed in clashes Uighurs and Han.

Ahead of the fourth anniversary of the incident on Friday, the overseas World Uyghur Congress plans to hold commemorations for victims, while police in Urumqi have begun 24-hour patrols.

In addition, Tianshannet reported, authorities have pledged 50,000 ($8,200) to 100,000 yuan rewards for people who provide tips that help solve "violent or terrorism cases".

They have published a list of 11 "most wanted" suspects, including two accused of killing security guards and construction workers in June, and three suspected of making explosives in a plan to attack government buildings.

Police also instructed anyone possessing "dangerous knives, explosives and propaganda materials on terrorism or violent crimes" to hand them in within 10 days to avoid punishment.

In the first of last week's incidents, the Xinhua state news agency said "knife-wielding mobs" attacked police stations and other sites in Lukqun township on Wednesday before officers opened fire, leaving 35 people dead.

It was the deadliest unrest reported in Xinjiang since the 2009 riots.

Two days later, in Hotan city more than 1,000 kilometres (600 miles) away, Xinhua said, 100 "terrorists" provoked "riots" and attacked people "after gathering at local religious venues".

"Terrorist activities" were against humanity, the China Daily said in an editorial Wednesday, adding: "The response has to be resolute and ruthless."

Information is tightly controlled in Xinjiang, and two AFP reporters trying to visit Lukqun last week were denied entry and temporarily detained.