A Chinese court on Monday condemned 12 people to death and gave another 15 suspended death sentences in connection with a July attack in violence-racked Xinjiang, the regional government's Tianshan portal said.

Thirty-seven civilians and 59 "terrorists" were killed and another 13 civilians wounded in the July 28 attack on a police station and government offices in Shache county, also known as Yarkand, according to state media.

The incident was the bloodiest in Xinjiang since rioting involving members of China's Han majority and the mostly Muslim Uighur minority -- the largest group in the region -- left around 200 people dead in the capital Urumqi in 2009.

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

"In adjudicating the case, the court fully implemented the criminal policy of combining justice with mercy," Tianshan said.

In addition to the 15 given a suspended death sentence -- normally commuted to life imprisonment, depending on the convict's behaviour -- nine people were sentenced to life in prison and 20 were given sentences ranging from four to 20 years, according to Tianshan.

State broadcaster China Central Television ran footage from the sentencing on its Monday evening broadcast, showing several defendants standing in court wearing bright orange prison vests and with their heads shaved.

Prosecutors showed images of large vehicles and axes they said were used in connection with the attack.

Overseas-based Uighur exile groups have cast doubt on the government's version of events in July, saying that Beijing's security forces used submachine guns and sniper rifles, leading to "huge casualties".

Access to information in Xinjiang is strictly controlled by the authorities and reports can often not be independently verified.

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.

- 'Strike hard' -

The sentences are the latest in a series of harsh punishments by Chinese authorities, who are in the midst of a "strike hard" campaign against violence in Xinjiang.

Last month a court in the ancient Silk Road oasis of Kashgar sentenced to death two teenagers for the killing of the government-appointed head of the country's biggest mosque.

The imam, Jume Tahir, was killed after leading morning prayers on July 30, two days after the Yarkand incident.

Another three people were given death penalties earlier in September over a mass stabbing that left 31 people dead in the southwestern city of Kunming in March.

In August China announced the execution of eight people for "terrorist attacks", including three who were described as masterminding a fiery car attack in Beijing's Tiananmen Square in October last year.

Violence in the region has intensified in recent months.

In May 39 people were killed, along with four attackers, when assailants ploughed two vehicles through a market in Urumqi and threw explosives, state media said.

In the latest incident, reported on Monday, a pregnant Uighur policewoman was stabbed to death by two "thugs" in Pishan county last Friday.

In September, 40 "rioters" were killed after a series of explosions in Luntai county, in an incident that also claimed the lives of six civilians, two police officers and two auxiliary police.

The violence took place just two days before prominent Muslim Uighur scholar Ilham Tohti was convicted of separatism and sentenced to life in prison.

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.