Addressing reporters in the Tajik capital Dushanbe, Niyozov said that despite a court ruling saying that Mahmadruzi Iskandarov should serve his jail sentence in a penal colony, he is still being held in a Justice Ministry prison cell.
Niyozov said he believed there is a link between the fact that Islandarov has not yet been transferred to a prison colony and the upcoming presidential elections due to take place in November.
"From the onset, Iskandarov's case was political," he said. "Things are getting more serious as we're getting nearer to new political developments. The authorities have one aim: to keep [Iskandarov] isolated. And this has gotten to the point that they're trying to cut him off from the outside world."
Niyozov said Iskandarov is denied the right to read newspapers or to see his relatives and attorneys.
There was no immediate comment from the Justice Ministry.
Iskandarov's friends and relatives say Iskandarov, who was living in self-exile near Moscow, was abducted last year and forcibly brought back to Dushanbe to be tried.
Tajikistan's Supreme Court last October sentenced Iskandarov to 23 years in jail on terror-related charges, charges that he denies.