SHANGHAI - Two men have been arrested on suspicion of cutting up and stealing a century-old bridge in the uptown Fengxian district, a case experts say should serve as an alarm to protect historic buildings in suburbs.

The two suspects, surnamed Hong and Wang, both from Anhui province, are being held in criminal detention and the district procurator's office is reviewing the case.

The bridge was in Chenyi village of Nanqiao town, surrounded by construction sites and with few passers-by. In November, a villager, Xie Chuquan, discovered that only the two supports of the bridge remained among the weeds.

Police interviewed people in the area, and a man said he had seen a truck with several men lingering near the bridge one night in September. He became suspicious and wrote down the license plate number of the truck, which he gave to police.

Police traced the number to the truck's owner, who said he had loaned the truck to the suspects that evening.

"The two men confessed that they used two cranes and two trucks that night to lift and remove the 16 stone pieces that formed the floor of the bridge," said Ruan Jilong, deputy director of Jinhai police station in Fengxian district.

Ruan said that Hong, who is a trader in building stones, paid Wang 30,000 yuan ($4,700) to transport the bridge, and the stones were resold to a salesroom at a park in Suzhou, Jiangsu province, which is owned by Hong.

Fengle Bridge, built in 1907, the 33rd year of the reign of Emperor Guangxu of the Qing Dynasty (1644-1911), is registered as a historical relic, though it is not on a city or national preservation list, according to Zhang Weiwei, director of Fengxian district museum.

"We've invited professors from Shanghai Jiaotong University to draw up a renovation plan for the ancient bridge. The reconstruction may cost at least 500,000 yuan, and will be completed this year," added Zhang.

He said Fengxian, which boasted more than 100 bridges a century ago, now has 20, including Fengle Bridge.

Zhang was not aware of similar cases in the district in recent years, but experts said the government should be alerted to the preservation of ancient bridges in outskirts during rapid urbanization.

"Nobody cares about bridges since the modern roads have been built," said Ruan Yisan, an expert on ancient buildings at the school of architecture and urban planning in Shanghai's Tongji University.

"I have seen bridges in suburban areas of the city that were built during the Song Dynasty (960-1279) and now have only their railings intact.

"And it wasn't just a few people who cashed in on selling old bridges to gardens in Jiangsu and Zhejiang provinces when Wuzhen and Xitang (towns in Zhejiang) underwent renovation for commercial development in recent years," he continued.

According to Ruan, villagers sell ancient bridges for several thousand to tens of thousands of yuan, but the price can multiply after changing hands through several brokers.

"What's more, some bridges were even sold as building stone," he said.

Experts said legislation can help safeguard the ancient buildings and deter lawbreakers from selling or exporting them.

"It is now considered a crime to resell a historic relic. But very few old constructions can be listed as such, although they are all precious and their values increases as time passes," Ruan said.

A micro blog user going by the name fengxianjun said he heard so many stories about Fengle Bridge in his childhood, and it was the only way to get to one of his relative's decades ago.

"Even if all the stones have been retrieved (by the police), it is no longer the bridge it used to be."