Prosecutors in Tajikistan last week opened the criminal trial of Makhamadruzi Iskandarov, an opposition leader who is accused of involvement in terrorism and creating an illegal armed group in the Central Asian republic. The trial comes four months after he disappeared from this Moscow suburb under circumstances that he describes as a kidnapping.

Iskandarov, who denies all the accusations against him, charges that he was seized by Russian police and transported to Tajikistan in what has come to be known as a rendition, the secret transfer of terrorism suspects between countries without any court proceeding. Iskandarov, leader of the Tajikistan Democratic Party, said he was kidnapped 11 days after the Russian prosecutor general's office denied an extradition request by the Tajik government.

He surfaced in a jail in the Tajik capital, Dushanbe, where his trial began on Aug. 2.

"Do I have absolute proof that he was kidnapped by the Russian authorities? No," said Anna Stavitskaya, Iskandarov's Russian attorney. "But without the participation of the Russian security services, his transportation would not have been possible."

Human right organizations said Russian authorities have become emboldened by reports about the U.S. practice of what the CIA calls "extraordinary renditions." Since the Sept. 11, 2001, attacks, the United States has secretly shipped dozens of suspects to countries in Central Asia, North Africa and the Middle East that practice torture.

"The Russian authorities are completely free in this situation," said Yelena Ryabinina of Civil Initiative, a human rights group that works with refugees in Russia. "The West cannot complain, and if they do, our leadership can say, 'Look at you, you do the same thing.' It's very sad."

Russian prosecutors declined to discuss the case.

On April 4, after spending four months in a Russian detention center, Iskandarov was freed when the prosecutor general's office refused to extradite him. Iskandarov said he then moved to a friend's apartment in this Moscow suburb and applied for refugee status in an attempt to protect himself from deportation under international law until his case was adjudicated.

Late on the evening of April 15, as Iskandarov walked near his friend's apartment on Soviet Street here, two Russian policemen and a group of plainclothes agents surrounded him, handcuffed him and forced him into a car, according to a statement Iskandarov later gave to his attorneys in Dushanbe. He said he was driven a short distance to a sauna, and on the following night, he was handed over to a second group of men in a nearby forest.

"Those new men put a mask on my face and an additional mask on my eyes and kept me there handcuffed for about an hour," said Iskandarov in his statement. His captors, he said, spoke Russian without an accent.

Iskandarov was then driven for about 30 minutes to an airport, both he and his attorneys said. "Then they put me on the plane," he said, and the following morning he reached Dushanbe, still masked.

His attorney noted that the only airport in the vicinity was the Chkalovsky military airport, 10 miles from Korolyov, site of the Russian space program's mission control.

Russian human rights groups cited other cases in which suspects have been subjected to renditions over the past two years. Some were sent to Uzbekistan, also the destination of some suspects seized by U.S. agents.

In May 2003, Rivazhiddin Rakhmonov, an Uzbek and the son-in-law of an Islamic leader, was detained on an extradition warrant in Marx, a city on the Volga River where he had lived in exile for 10 years. Uzbek authorities accused Rakhmonov of "religious extremism," a charge often leveled by Uzbek authorities against those who refuse to participate in government-sanctioned Islamic activities.

Russian officials rejected the Uzbek extradition request, and Rakhmonov was released. He disappeared that day without having contacted his family, according to Memorial, a Russian human rights group. Rakhmonov resurfaced in a prison in Uzbekistan and was sentenced in January 2004 to an eight-year term.

His father-in-law, Mannobzhon Rakhmatullayev, also an exile, was involved in a similar case. Rakhmatullayev, 54, was detained by Russian authorities in October 2002, also on Uzbek charges of religious extremism. Uzbek officials claimed he made an unauthorized pilgrimage to Islamic holy sites in Saudi Arabia in 1992.

A Russian court ordered his release the following month, but he was immediately rearrested on a new extradition warrant that carried new charges, including terrorism, inciting religious and ethnic strife and threatening Uzbekistan's constitutional order. The Uzbek government alleged that he was a member of Hizbut Tahrir, a group that says it seeks the peaceful reestablishment of the caliphate, a central Islamic order across the Muslim world.

In October 2003, the Russian prosecutor general's office again refused the extradition request and Rakhmatullayev was released. On July 21, 2004, three masked men grabbed Rakhmatullayev as he and his wife, Makhbuba, walked to a local market where they sold clothing, human rights organizations reported.

Several weeks later, Russian authorities informed the family that Rakhmatullayev was in Uzbek custody. In January, Rakhmatullayev was sentenced to 16 years in prison following a closed trial in Andijan, the Uzbek city where hundreds of protesters were killed in a government crackdown in May.

Rakhmatullayev's family, including his wife, followed him to Andijan and could not be contacted to discuss the case. But in an interview late last year with a Russian Web site, www.Islam.ru, his wife said: "I walked a lot trying to find my husband. But I never saw him again."

In each of the reported abductions, Russian prosecutors have opened criminal investigations, but they did not respond to requests for information on those probes.

Human rights groups are now concerned about the fate of Alisher Usmanov, 43, originally from Uzbekistan, who recently disappeared from Kazan, capital of the semi-autonomous Russian republic of Tatarstan. Usmanov, who taught Islamic law in Kazan, had just finished a nine-month prison sentence for illegal possession of explosives. Usmanov had denied the charge, saying police had planted a grenade and other material in his apartment.

When Usmanov's family arrived at the jail to pick him up on the morning of June 29, according to Ryabinina of the Civil Initiative group, prison officials said they already had let him go. The family said they have been unable to locate him.

Memorial, the human rights group, and other organizations said they now believe he also was secretly transferred to Uzbekistan where he was first placed on a wanted list in 1998. Russian officials had refused an Uzbek extradition request because Usmanov had obtained Russian citizenship. Uzbek officials have not acknowledged that they have him in custody.

In the case of Iskandarov, Tajik officials quickly acknowledged his arrest, but reportedly said he had tried to enter the country secretly on a false passport and was arrested him at the airport.