At least four or five people whom the police suspect were behind the bombings were killed or injured in the explosions in Kuqa county in the Muslim region of Xinjiang, the official Xinhua News Agency said, citing local sources.
The agency had said in an earlier dispatch that at least two people were killed in the attack, and cited witnesses as saying they saw flashes of fire and heard gun shots following the explosions, which took place before dawn.
Xinhua said local military sources confirmed the incident and said they have deployed forces to the area, while police have sealed off the area where the explosions occurred. Kuqa is 460 miles from Urumqi, the regional capital.
A woman who was on duty at the emergency unit of the Kuqa People's Hospital said one man was pronounced dead upon arrival while several other people were in critical condition.
"There were several explosions in several places in the county seat of Kuqa this morning and we heard them from the hospital," said woman, who would only give her last name, Tian.
Citing accounts from Uighurs at the scene, activist Dilxat Raxit said the explosions hit government offices and public security and military police posts.
A man who answered the phone at the Kuqa county government's duty office said he was not aware of the explosions and refused to give his name. Repeated calls to the county's public security bureau rang unanswered.
The latest violence comes after two Americans closely linked to the U.S. Olympic volleyball team were stabbed, one fatally, in a bizarre attack Saturday in the Chinese capital on the first day of the Beijing Games.
Already normally tight security in Xinjiang was increased in the past week after assailants killed 16 border police and wounded 16 others in the city of Kashgar on Monday when they rammed a stolen truck into the group before tossing homemade bombs and stabbing them.
The explosions also come after an Islamic group seeking independence for Xinjiang province threatened Thursday to attack buses, trains and planes during the two-week Olympic competition.
A videotape purportedly made by the Turkistan Islamic Party, a militant group seeking independence for Xinjiang, was released with threats of attacks during the Olympics. The group is believed to be based across the border in Pakistan, where security experts say core members have received training from al Qaeda.
Xinjiang is a massive, rugged territory one-sixth of China's land mass that's home to the Uighurs, a Muslim minority with a long history of tense relations with the Chinese. The Uighurs, with a population of about 8 million, have complained that the Communist government has been restricting their religion and Turkic culture.
"We have been appealing to Beijing to solve the issue through political dialogue to prevent the situation from deteriorating, but they have never taken it seriously," Raxit, spokesman for the Germany-based pro-independence World Uighur Congress, said in an e-mail. "On the contrary, they heightened the suppression. Beijing should be directly responsible for today's incident."
Beijing has accused Uighur groups of using terrorism in a violent campaign to split Xinjiang from the rest of the country. China's state-run media have reported sporadic bombings, shootings and riots in the territory over the years, but the dispatches are often sketchy and difficult to verify.
A county of 400,000 people, Kuqa is a popular tourist destination in Xinjiang and is rich in oil and gas resources.