An overseas-based Uighur exile group on Tuesday denounced the sentencing to death of 12 people in China's Xinjiang, saying the government's approach "will invariably exacerbate an already tense situation" in the far-western region.

Xinjiang, home to China's mostly Muslim Uighur minority, has been racked by violence, with incidents becoming increasingly severe in recent months and also taking place far outside the region.

"Death sentences have become increasingly common in the region with scores of others suffering the same fate in the past few months," the World Uyghur Congress said in a statement.

"The increase in frequency of these trials and sentences signals that the state has stepped up its one-year anti-terror campaign by exhibiting excessive force against its population," it added.

The statement came one day after a Chinese court condemned 12 people to death and gave another 15 suspended death sentences in connection with a July attack on a police station and government offices in Shache county, also known as Yarkand.

A total of 37 civilians and 59 "terrorists" were killed in the attack, according to state media.

The incident was the bloodiest in Xinjiang since rioting involving Uighurs -- the largest group in the region -- and members of China's Han majority claimed the lives of around 200 people in the capital Urumqi in 2009.

The sentences brought the number of death penalties announced for Xinjiang-related violence to almost 40 since June, with 21 executions publicly declared.

Beijing has blamed a series of recent violent attacks on separatists from Xinjiang. Rights groups accuse China's government of cultural and religious repression which they say fuels unrest in the region bordering Central Asia.

Chinese authorities are in the midst of a "strike hard" campaign against violence in Xinjiang that has also seen prominent Uighur academic Ilham Tohti sentenced to life in prison for separatism.

International rights groups have called for Tohti's release and denounced the trial, which they say was retribution for the scholar's outspoken criticism of Communist Party policies towards Uighurs.

The World Uyghur Congress said that since the campaign began, "security and police have taken any and every opportunity to exercise force against Uighurs".

"If the only tool you have is a hammer," the group said, it is tempting "to treat every problem as though it were a nail".

"China's approach to Uighur dissent has solely been to treat Uighurs as terrorists and innocent civilians as collaborators."