Clashes that killed 12 people in China's western region of Xinjiang were caused by "terrorists", Chinese state media report, citing police.

Six people were shot dead by police and six were killed in explosions in Xinjiang's Aksu prefecture on Friday, state media said.

Xinjiang, home to the Muslim Uighur minority group, sees sporadic clashes.

Verifying reports from the region is difficult because the information flow out of Xinjiang is tightly controlled.

Authorities traditionally blame extremists for outbreaks of violence, while Uighur activists point to tight Chinese control as a cause of tensions.

Uighurs and Xinjiang Uighurs are ethnically Turkic Muslims

They make up about 45% of the region's population; 40% are Han Chinese

China re-established control in 1949 after crushing short-lived state of East Turkestan

Since then, large-scale immigration of Han Chinese

Uighurs fear erosion of traditional culture

State-run news agency Xinhua said explosions took place at a hair salon and market on Friday afternoon.

After the blast, police shot six suspects, while another six died when they set off explosives, the news agency said, adding that five other people had been arrested.

Xinhua news agency described the incident as "organised, premeditated terrorist attacks". But the report gave no reason why the hair salon and the market were targeted.

Dilxat Raxit, a spokesman for exiled Uighur group the World Uighur Congress, suggested that the protests were sparked by anger at the salon because it was a front for a brothel.

"The forced repression and provocation is the real reason for the confrontation," he said in a statement.

'Disturbing pattern'

Meanwhile, on Saturday, Chinese state media reported that Ilham Tohti, a Beijing-based scholar from the Uighur ethnic group, was being investigated for "separatist activities".

Image copyright AP Image caption Mr Tohti is an economist at a university in Beijing

The outspoken scholar, who is known to be critical of China's ethnic policies, has been detained since 16 January.

The US State Department said his detention appeared "to be part of a disturbing pattern of arrests and detentions of public interest lawyers, Internet activists, journalists, religious leaders and others who peacefully challenge official Chinese policies and actions".

Xinjiang has experienced several violent clashes in recent months, and its unrest has been linked to other attacks in China.

In December, 16 people were killed in a riot in a village near the city of Kashgar, and another eight were killed later that month in Yarkland county.

In late October, five people were killed when a car ploughed into a crowd and then burst into flames in Beijing's Tiananmen Square.

Beijing called the incident a terrorist attack inspired by Xinjiang-linked extremists. Three people who died inside the car were identified by police as Xinjiang Uighurs.