BEIJING -- An American businessman stood trial in China on Monday for allegedly heading a violent mob that kidnapped rivals and operated illegal casinos, charges he's said he was tortured into confessing.

Authorities in southern China have accused Vincent Wu of gang crimes but Wu's family and lawyers say he's a law-abiding businessman whose rivals have framed him to seize his assets.

"We are still very confident because our lawyers have all the evidence to prove that he is innocent," said Wu's daughter, Anna Wu, by phone from Guangzhou. "We believe we still have a chance and so we'll hope for the best."

Wu's lawyers urged a court in the southern city of Guangzhou to recognize the defendant's American citizenship as he and more than two dozen associates stood trial.

Wu has been denied U.S. consular access since his detention in June 2012 despite being a U.S. passport holder who shuttles between his family in Los Angeles and his business in China.

China refuses to acknowledge Wu's American citizenship because his last entry into mainland China was made on his Hong Kong residence pass.

The case underscores the risks faced by individuals working in China who have travel documents from more than one country because Beijing does not recognize dual nationalities.

Two U.S. consular officials attended Monday's hearing and told the court the American government recognized Wu's U.S. citizenship but judges rejected their assertion, said Wu's legal adviser, Li Zhuang.

The Guangzhou Intermediate People's Court and the U.S. Embassy in Beijing had no immediate comment.

Wu, who was seeing his family and friends for the first time since he had been taken away nearly two years ago, appeared emotional, his daughter said. "He kept saying 'I'm an American citizen, you have to give me a fair trial,"' Anna Wu said.

The case exposes the murky environment in which businesses in China often operate. Widespread corruption allows entrepreneurs to cozy up with police and run roughshod over the law to take down their rivals.

Wu is charged with getting an associate to throw acid at a judge who ruled against him in a lawsuit, and with ordering thugs to set fire to sheds owned by farmers who refused his offer of compensation to clear off land he wanted to develop.

Wu is also accused of operating illegal casinos that raked in $7.8 million and of attacking or kidnapping people who crossed him in various disputes.

The businessman has also alleged that he was tortured in detention, telling his lawyers he had been beaten, kicked and strung by his arms from a ceiling beam as police tried to coerce him to sign a confession.

Wu left China in the late 1970s as a stowaway to neighbouring Hong Kong, where he obtained residency. He moved with his family to the U.S. in 1994, settled in Los Angeles and eventually became a U.S. citizen.