BEIJING — China has detained 82 suspected terrorists in the first half of the year on allegations that they were plotting attacks against next month's Olympics, according to state media reports Thursday.

The reports appeared to bolster human rights groups' claims that authorities were ratcheting up security and repression to shield the games from disruptions that could tarnish China's carefully crafted image of order and control.

Police nabbed the suspects in raids on five separate terrorist rings in the traditionally Muslim Xinjiang region of China's far west, regional police chief Chen Zhuangwei was quoted as saying by newspapers and the official Xinhua News Agency.

Separatists among Xinjiang's indigenous Turkic Uighur people have been fighting Chinese rule for decades. Critics say communist authorities fuel resentment with harsh repression and strict limits on cultural and religious expression.

"All officers recommit themselves to stepping up the fight against terrorism" and other threats, Chen was quoted by local newspaper Xinjiang Metropolitan as telling a news conference in the regional capital, Urumqi, on Wednesday.

"We must perfect the emergency response and command system, solidly carry out Olympic security work and ensure security in the regional capital," Chen said.

Officers reached by phone at Xinjiang's regional police headquarters on Thursday said they were unable to comment on the news reports and no spokesmen were available.

The reports gave no breakdown of individual cases, although China has announced a series of raids and says it has busted plots to crash an airliner, carry out bombings, and kidnap athletes and journalists during the games.

On Wednesday, Xinhua said police shot dead five members of a radical Islamic separatist group in Xinjiang, as officials called for an all-out security push ahead of the Aug. 8-24 games.

No hard evidence was offered to back up the claims, although terror experts say Beijing faces a significant threat from the East Turkestan Islamic Movement, an al-Qaida-linked radical group fighting to establish an independent Islamic state in far western China.

Police were seeking another 66 radicals associated with terrorism, religious extremism and separatism, the reports said. Also in the crackdown, 51 criminal gangs were smashed, netting 217 suspects and 268 wanted criminals.

Police also raided 41 locations identified in the reports as "illegal religious schools" and "jihad training centers," the reports said. China allows worship only in state-sanctioned mosques, churches and temples and forbids Uighur Muslim children from attending services.

No figures were given for casualties among police and suspects, although Chinese media reports have said at least seven suspects have been killed this year, while 18 were killed last year in a raid on a training base allegedly run by the East Turkestan Islamic Movement.

With the games just weeks away, Chinese officials are ordering increasingly draconian security measures, with a dual ring of hundreds of checkpoints due to go up around Beijing starting next week.