China has detained 29 people described as "terrorist suspects" in its ethnically divided western region of Xinjiang, state media said Thursday, as authorities crack down following several deadly attacks.

Suspects detained in Xinjiang's capital Urumqi face charges including "inciting separatism" and "disturbing order in a public place", the state-run Xinjiang Net said.

In the past year Xinjiang -- home to the mostly Muslim Uighur minority -- has seen an increase in violent clashes, which Beijing blames on organised terrorist groups seeking independence for the region.

The 29 cases were processed according to new rules calling on state prosecutors to complete terror-related investigations within 24 hours, the report said.

Critics say the terror threat in Xinjiang is exaggerated by Beijing to justify hard-line measures, and point to economic inequality and cultural and religious repression of Uighurs as causes of unrest.

China last month vowed a year-long campaign against terrorism, after attackers in Urumqi killed 39 people in a suicide raid on a marketplace.

Assailants armed with knives and explosives carried out an attack at a railway station in the city in April, killing one person and wounding 79 as President Xi Jinping visited the region.

Authorities in Xinjiang last week sentenced 55 people for offences including terrorism at a mass gathering in a stadium attended by about 7,000 people. Hundreds of others are reported to have been detained in recent weeks.

Information about Xinjiang, a vast and resource-rich region bordering Central Asia, is difficult to verify independently, with foreign and local journalists subject to heavy restrictions.