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By John Ruwitch

JINAN, China, Aug 22 (Reuters) - Fallen politician Bo Xilai put up a feisty defence on Thursday as he faced China's most political trial in decades, saying he was framed in one of the bribery charges against him and had admitted to it against his will during interrogation.

The 64-year-old former Communist Party chief of the southwestern city of Chongqing has been charged with illegally taking almost 27 million yuan ($4.41 million), corruption and abuse of power and will almost certainly be found guilty.

Bo's denial of one of the charges and strong language as he made his first public appearance since being ousted early last year were unexpected. But at least one observer said he could have struck a deal with authorities to show he was getting a fair trial in exchange for a pre-arranged sentence.

President Xi Jinping is seeking unstinted support from the Communist Party as he seeks to push reforms that will rebalance the economy, and will want Bo's trial to be finished quickly and with a minimum of fuss.

"He (Bo) is clearly going along with this trial," said Nicholas Bequelin, a researcher for New York-based Human Rights Watch. "The outcome has been already decided. There's probably an agreement already between Bo and the party as to what the outcome will be."

Bo's downfall has pitted supporters of his Maoist-themed egalitarian social programmes against the capitalist-leaning economic road taken by the leadership in Beijing, exposing divisions within the ruling party as well as Chinese society.

Bo was one of China's rising political stars and his trial in the eastern city of Jinan marks the culmination of the country's biggest political scandal since the 1976 downfall of the Gang of Four at the end of the Cultural Revolution.

Appearing sombre, a clean-shaven Bo, whose hair looked like it was still dyed black, stood in the dock without handcuffs, according to a picture issued by the court. He was dressed in a long-sleeved white shirt and stood with his hands crossed in front of him, flanked by two policemen.

Foreign media were not allowed to attend the trial and Bo's remarks were carried on the court's official microblog, so are likely to have been highly edited. Still, the transcripts provided by the court mark a level of openness that is unprecedented for a trial in China.

"Regarding the matter of Tang Xiaolin giving me money three times, I once admitted it against my will during the Central Discipline Inspection Commission's investigation against me," Bo said, referring to the party's top anti-graft body.

"(I'm) willing to bear the legal responsibilities, but at that time I did not know the circumstances of these matters: my mind was a blank," he added.

"MAD DOG"

Bo was charged with receiving about 21.8 million yuan ($3.56 million) in bribes from Xu Ming, a plastics-to-property entrepreneur who is a close friend and is in custody, and Tang, the general manager of Hong Kong-based export company Dalian International Development Ltd, the court said.

Bo called Tang "a mad dog" who wanted to "frame me out of consideration for his own interests".

"This evidence has little to do with my criminality," Bo said. "I was just hoodwinked. I thought it was all official business."

Bo received the bribes through his wife, Gu Kailai, and his son, Bo Guagua, the court said, citing the indictment.

It was the first time that authorities had named the younger Bo in the case against his father. Guagua is now in the United States, pursuing a law degree at Columbia University.

Bo Guagua was not immediately available for comment.

Tang's whereabouts are unclear. A secretary at Dalian International's office in Hong Kong said she had not seen Tang since May or June last year. There was also no one at his last known residential address in Hong Kong.

Written evidence from Gu was provided to the court in which she said she had seen a large amount of cash in safes at two of their residences, money which matched the amount alleged given to Bo from Tang.

Bo said that testimony was "laughable".

Bo's trial will last for two days and the verdict is likely to be in early September, state broadcaster CCTV said.

Court spokesman Liu Yanjie said Bo was "emotionally stable and physically healthy" during the trial.

The Jinan Intermediate Court said on its microblog feed that five of Bo's family members attended the hearing. In another picture published by the court, Bo's siblings appeared to be in court. The court said over 100 people filled the courtroom.

Underscoring popular support for Bo, a handful of supporters protested outside the courthouse for a second day to denounce what they said was politically motivated persecution. Police, who had blocked off the courthouse, hustled them away.

Bo also embezzled 5 million yuan from a government project in the northeastern city of Dalian, where he served as mayor, the court said.

The charge of abuse of power against Bo relates to the murder case involving Gu, the court said. Bo was a rising star in China's leadership circles when his career was stopped short last year by the murder scandal involving Gu, who was convicted for the November 2011 murder of British businessman Neil Heywood, a business partner and family friend.

Bo's former police chief in Chongqing, Wang Lijun, has also been jailed for trying to cover up the case. Bo was furious with Wang when he was told that his wife was a murder suspect, and sacked him despite not having party authority to do so, sources with knowledge of the case have said.

Neither did he report the matter to his bosses in Beijing, all of which led to the abuse of power charge, they said.

Bo could face a death sentence for his charges, though a suspended death sentence is more likely, which effectively means life imprisonment, or a 20-year term.

His guilt is an almost foregone conclusion given that prosecutors and courts come under Communist Party control. ($1 = 6.1234 Chinese yuan) (Additional reporting by Judy Hua in JINAN; Sui-Lee Wee, Hui Li, Megha Rajagopalan and Ben Blanchard in BEIJING; and James Pomfret in HONG KONG; Writing by Sui-Lee Wee; Editing by Ben Blanchard and Raju Gopalakrishnan)