At least 18 police officers were killed after ethnic Uighurs launched a coordinated attack in China's Xinjiang province, in what has been seen as a response to Beijing's recent fasting ban during Ramadan.

According to Radio Free Asia, the attack took place in the Tahtakoruk district of western Xinjiang province.

Unconfirmed reports suggest the death toll could be as high as 28 as those who were killed included onlookers.

"When one of the policemen at the checkpoint ran out of the booth, the car backed up, hitting him and breaking his leg. Two other suspects then rushed out of the car, using knives to attack and kill two police officers who had come to rescue their comrade," Turghun Memet, a police officer with the Heyhag district police station, was cited as saying.

Tensions between the Muslim Uighurs - who call themselves natives of the region - and the Han Chinese - who are the majority - have been rising in recent years along with increasing bloodshed in the region.

Local police said the onslaught was carried out by "terrorists" squarely blaming the Uighur extremists.

The attack is widely seen as retaliation by the fighters after Beijing imposed harsh restrictions on Ramadan, a month which is considered holy by Muslims. It is believed that this is not the first time the Uighurs have launched knife attacks in the region.