A bridge under construction in an ancient Chinese city collapsed as workers removed scaffolding from its facade, killing at least 29 people, the government said Tuesday.

The 140-foot-high bridge spanning the Tuo River in the central Hunan city of Fenghuang collapsed Monday, the Hunan Administration of Work Safety said in a statement posted to the official Gov.cn Web site. The span in Hunan's Fenghuang county, intended for both pedestrian and vehicle traffic, had four decorative stone arches and was scheduled to open at the end of the month, the administration said.

• PHOTO ESSAY: Bridge Collapse

At least 28 people were killed and 86 people were rescued, including 22 who were injured, the official Xinhua News Agency said. An estimated 123 workers were at the site at the time.

Premier Wen Jiabao ordered a thorough investigation into the collapse of the 880-foot bridge, China Central Television reported.

The accident came less than two weeks after the collapse of a bridge in Minnesota that drew attention to aging transport infrastructure in the United States.

Surrounded by lush mountains and rice paddies, the ancient city of Fenghuang is a well-known tourist spot and home to the Miao and Tujia ethnic minorities. It is also famed for traditional stilt houses lining the Tuo River.

China Central Television showed bulldozers plowing through the rubble, overturning chunks of stone and concrete mixed in a tangle of steel reinforcement bars. News photos showed anxious and weeping villagers waiting for news about their loved ones.

Most of the people working on the bridge were local farmers, the agency said.

"I was riding a bike with my husband and we had just passed under the bridge and were about 50 meters (160 feet) away when it collapsed," said a witness who would only gave her surname, Wu. "There was a huge amount of dust that came up and didn't clear for about 10 minutes."

Yang Long, a villager whose home was just a dozen yards from the site, described a grim rescue effort. "Their arms and legs were broken, only linked with skin," he said of bodies being pulled from the rubble.

Wu, a cleaning lady at a local hotel, said there were houses underneath the bridge and she had heard that friends who lived there had died.

The safety administration said the bridge was designed by the Hunan Huagang Transportation Design Institute in the provincial capital of Changsha.

Xinhua said the bridge was a $1.6 million project by the Fengda company of western Hunan, without giving the company's full name. An employee of a Fengda Road Construction Co. in Fenghuang said he was not clear if the bridge project was his company's. He refused to give his name.

Xinhua identified the contractor as the state-owned Hunan Road and Bridge Construction (Group) Ltd. Co., or RBC. RBC's construction manager and project supervisor were detained for questioning, it said. Phone numbers listed on the company's Web site rang unanswered Tuesday.

Construction accidents in China are frequent, with contractors often opting for shoddy materials to cut costs and using migrant laborers with little or no safety training.

The Fenghuang collapse is among the worst in recent memory. On June 15, a bridge in south China's Guangdong province collapsed when a cargo vessel loaded with sand rammed into it, killing nine people. That bridge was built in 1988 and spanned the Xijiang River, a major tributary of the Pearl River.

In January 1999 a pedestrian bridge spanning the Qi River in southwestern China's Sichuan province collapsed three years after it was built. Forty people died and another 14 were injured.

Following the accident, a local county deputy party secretary was sentenced to death for accepting a bribe from a childhood friend in exchange for the bridge-building contract.

The accident highlighted concerns among Chinese leaders and the general public about breakneck development and pervasive corruption among officials.

In its annual report on road safety last year, the Ministry of Communications categorized 6,300 of the country's bridges as dangerous because of serious damage to their "structural components," the China Daily newspaper reported Tuesday.

The newspaper report quoted Xiao Rucheng, secretary general of China's Institute of Bridge and Structural Engineering, as saying that China should "learn a lesson from the Mississippi bridge and accelerate the inspection of unsafe bridges," referring to the Aug. 1 collapse of the bridge in Minnesota that killed at least nine people.

The China Daily also ran an editorial Tuesday saying rising traffic levels made the need for nationwide bridge repairs and upgrades an urgent issue.

"If left unrepaired these bridges may crumble at any time, (wreaking) economic havoc and possibly claiming human lives," it said, without mentioning the Fenghuang disaster, which was not reported by state media until late Monday.