A Moscow court rejected a request by lawyers for former Yukos CEO Mikhail Khodorkovsky to replace the state prosecutors as preliminary hearings opened into his second trial Tuesday.

Khodorkovsky was all smiles as he greeted business partner and co-defendant Platon Lebedev in the defendant's cage and silently listened to the afternoon proceedings.

Outside the court, police broke up a small rally of about a dozen people supporting Khodorkovsky, detaining several people.

Two former Yukos oil units also announced that they had filed lawsuits seeking nearly $5 billion in damages for oil purportedly pilfered by Khodorkovsky and Lebedev.

The two men face new sentences of up to 22 1/2 years in prison if convicted on charges of embezzlement and money laundering connected to three production units formerly owned by Yukos.

Lawyers for the defendants asked the Khamovnichesky District Court to dismiss the prosecutors, Dmitry Shokhin and Valery Lakhtin.

"We have many arguments for their dismissal," Khodorkovsky lawyer Vadim Klyuvgant said. "We've gotten to know them well enough from the previous trial."

Shokhin was one of the prosecutors in first trial, which ended with Khodorkovsky being convicted of fraud and tax evasion and sentenced to eight years in prison. Shokhin subsequently was promoted to the rank of colonel.

Lebedev is also serving eight years.

The court on Tuesday rejected the request to dismiss the prosecutors.

The prosecutors refused to comment on the trial while leaving the courtroom Tuesday.

Khodorkovsky's lawyer Karina Moskalenko complained that the court had barred the defense team from speaking to the defendants during a break in the proceedings.

"But they are still full of determination," she said of the defendants, speaking to reporters outside the court.

Khodorkovsky and his supporters say the charges are politically motivated and are retribution from a Kremlin angered over his political and business ambitions.

Igor Tabakov / MT Armed officers watching the Khodorkovsky proceedings in court Tuesday.

Khodorkovsky and Lebedev were delivered to the court in a Ford prison vehicle in the afternoon. Khodorkovsky, wearing jeans and a black coat, and Lebedev, in gray sports pants and a winter jacket, were placed in a defendant's cage where the customary bars had been replaced with glass for the trial.

Peacefully smiling, the defendants did not seem to hear the journalists' questions through the glass before the hearings opened.

About 150 accredited journalists lined up outside the court before the trial, waiting to clear security to get inside. Most of the journalists represented foreign media, said Moscow City Court spokeswoman Anna Usachyova.

Reporters were led to a special viewing room equipped with three televisions hooked up to broadcast the trial from the courtroom upstairs. However, the reporters saw images of the courtroom crowded with photographers, cameramen and chattering lawyers for only about a minute before a court guard switched off the televisions. The reporters vented their frustration by clapping loudly.

About 300 police officers were stationed around the court on Rostovsky Pereulok in central Moscow to ensure security, Moscow police said. The area around the court was cordoned off, and police officers checked journalists' bags and documents.

Ordinary people were barred from the area, angering several pensioners who had to find alternative routes to their destinations.

A group of people tried to rally in front of the court in support of Khodorkovsky, but police quickly disbursed them, detaining several for violating public order. The police did not say how many were detained and whether they were still being held late Tuesday. City authorities on Monday rejected a request for a demonstration to support Khodorkovsky and Lebedev.

The defense lawyers said it was too early to estimate how long the trial would last. But Lebedev's lawyer Yelena Liptser predicted that it would continue for more than six months considering the 4,000 pages of charges.

Prosecutors accuse Khodorkovsky and Lebedev of embezzling oil worth more than 892.4 billion rubles ($25 billion) from Yukos production units and laundering a portion of the profits, 487.4 billion rubles and $7.5 billion.

They are accused of stealing oil from three Yukos production units from 1998 to 2003. Two of the units, Samaraneftegaz and Tomskneft, have filed lawsuits seeking 170 billion rubles in damages, Tomskneft official Andrei Pyatikopov said Tuesday, Interfax reported.

Samaraneftegaz, however, will probably not press through with the lawsuit because it recovered damages of 77 billion rubles from the sale of Yukos assets in bankruptcy auctions, he said.

A spokesman for state-owned Rosneft, which now owns Samaraneftegaz, declined to comment on the lawsuit. Rosneft and Gazprom Neft each own half of Tomskneft.

Anatoly Medetsky contributed to this report.