The Tajik authorities accused Iskandarov of organizing an attack against an Interior Ministry and local prosecutor's office in the eastern region of Tajikabad in August 2004.
He was also accused of embezzlement. Iskandarov rejected the charges as "ridiculous."
The Russian authorities released Iskandarov in April, after four months in custody. But two weeks later, he mysteriously disappeared from Moscow only to turn up under arrest in Tajikistan. He has been in custody there since.
On 20 June, U.S. Embassy official John Chamberlain reminded the Tajik authorities about their legal obligations to Iskandarov.
"The United States calls on the Tajik authorities to permit Mr. Iskandarov's access to his legal counsel in accordance with Tajikistan's own laws and international standards," Chamberlain said.
Chamberlain joins a growing chorus of criticism over Iskandarov's case. This month, in a statement to the Organization for Security and Cooperation in Europe (OSCE), U.S. Ambassador to the OSCE Stephan Minikes said Iskandarov "has been denied regular and unobserved access to his legal council and his family has been unable to meet with him."
Ambassadors from European Union countries accredited in Tajikistan sent a note to the Foreign Ministry at the beginning of the month demanding a meeting with Iskandarov, as a representative of an opposition political party. They have not yet seen Iskandarov, but reportedly his sister was allowed to visit on 26 June.
The Islamic Renaissance Party (IRP), another opposition party, is now claiming that it too is the victim of a campaign aimed at tarnishing its image.
Two IRP members were arrested in Khatlon province recently. The IRP claims the two were detained because they did not answer an "invitation" from the local prosecutor's office. Local IRP leader Hoja Kalandar Saddriddinzda questioned the entire case surrounding the two men.
"[IRP member] Saifiddin Faizov, resident of Bokhtar, and another Islamic Renaissance Party member were detained for hooliganism," Saddriddinzda told RFE/RL. "Also the prosecutor's office had asked them several times to come in for questioning. The Islamists say such an 'invitation' without concrete questions or a case aims to cast the party's image in a bad light."
The charge of hooliganism appears to stem from allegations that Faizov was using foul language in a mosque. In majority-Muslim Tajikistan that accusation certainly won't help the IRP.
Two members of yet another opposition group, the Social-Democrat Party (SDP), were also jailed last week in the northern Soghd region.
The SDP leader from Soghd's Mastcho District, Nizomiddin Begmatov, received one year in jail and Nasim Shukurov got 18 months for hooliganism. The SDP claims the two were imprisoned because on 27 February, parliamentary election day, they brought protests over the conduct of the poll to the district court head. The court official did not accept the protests.
"This verdict of the court is wrong and baseless and is made just because of an order from the [Soghd] provincial administration and the republic's government and the reason for this is only my attempt to be a deputy of Majlisi Namoyandagon," Begmatov said, shortly after his verdict was delivered. "They did not let us."
SDP leader Rahmatullo Zoirov says the party will appeal to a higher court.
In another sign of a government crackdown against the opposition, the unregistered Tarraqiyot (Development) Party has experienced more difficulties recently. The closed-door trial of the party's deputy chairman, Rustam Faiziyev, started last week. Faiziyev is charged with "insulting the president of the country" and inciting interethnic and regional hatred. Party leader Sultan Kuvvatov was detained on the same charges at the start of the year.
(Iskander Aliyev of RFE/RL's Tajik Service contributed to this report)