Oil tycoon Mikhail Khodorkovsky and his billionaire business partner pleaded from inside a courtroom cage Wednesday to be freed pending their upcoming trial on fraud and tax evasion charges, but were ordered back to prison.

Khodorkovsky and his associate, Platon Lebedev, were brought into a cramped courtroom in northern Moscow for the beginning of proceedings in a case widely seen as a political confrontation between Russia's richest man and its president, Vladimir Putin.

The trial will culminate a year-long legal campaign that could put Khodorkovsky in prison for 10 years and break up his Yukos oil company.

The day-long hearing Wednesday dealt mainly with procedural matters but offered the most extended public view of Khodorkovsky since his arrest at gunpoint in Siberia last October. Dressed in a brown jacket and denim trousers, the 40-year-old businessman appeared relaxed and joked with reporters during breaks.

When it came time to address the three-judge panel, Khodorkovsky condemned his eight-month pretrial detention as an illegal abuse of power that would only embolden the state to persecute others. "My case is a precedent for justice in general and it will lead to hundreds of people being held in detention before their trials," Khodorkovsky told the court as his elderly parents watched from the third row a few feet away. He asked to be placed under house arrest.

Lebedev, who has reportedly grown sick during nearly a year in custody, appeared weaker and more emotional than his business partner. As he stood to address the judges, he steadied himself on the bars of a cage, in which suspects are kept during appearances in Russian courts, and complained that he had been separated from his wife and family.

At stake in the trial, according to some analysts, is the relationship between the state and private enterprise in Russia's still evolving market economy. Khodorkovsky's international team of attorneys has portrayed it as a test case for the rule of law in a country where the justice system is still dominated by the executive branch of government.

Khodorkovsky ran afoul of Putin when he defied a Kremlin dictum for business leaders to stay out of politics, and the president's allies accused him of trying to buy influence in parliament.

"The whole world is watching," Robert Amsterdam, one of Khodorkovsky's foreign attorneys, said outside the courthouse. Amsterdam, a Canadian, told reporters he expected the court to find the defendants guilty, and said he would appeal the case to international tribunals.

As Khodorkovsky arrived at the courthouse, a few dozen supporters demonstrated outside. Inside, eight or nine guards kept people from talking with the defendants. "I asked, 'Can I just touch him?' " Khodorkovsky's father, Boris, said in an interview after approaching a guard. "He said, 'No, it's not allowed.' I can't even ask him how he feels."

The judges eventually allowed television crews to film the two longtime partners, who had not seen each other since Lebedev's arrest last July 2. The two chatted quietly during the hearing and shared what appeared to be a photo album of their children.

A reporter asked what they were talking about. "About everything," Lebedev said. "Mainly about our families," Khodorkovsky added.