Shiite leader Ibrahim El-Zakzaky has alleged that the conditions at the Indian hospital he was taken to is worse than that of Nigeria.
He said he plans to return to Nigeria to assess the situation.
Mr El-Zakzaky stated this in an audio message that has since gone viral.
PREMIUM TIMES has confirmed the authenticity of the audio.
The cleric, leader of the Islamic Movement in Nigeria (IMN), was flown to India on Monday following a Kaduna court order last week.
He had requested to be allowed to travel to India for advanced medical treatment following the deterioration of his health and that of his wife, Zeenah, in detention.
Both of them have been detained since December 2015 after a clampdown by soldiers who killed at least 347 IMN members.
In the audio, Mr El-Zakzaky accused the Nigerian government of frustrating his medical treatment in India.
Speaking in Hausa, he said the situation at the hospital in India is "pathetic and worrisome situation."
He said the management of Medanta Hospital, New Delhi, had been threatened not to admit him for treatment.
"The hospital officials received us well they told us that they parked two ambulance vehicles, deceiving the crowd while taking us out through another way, saying that it was for our own safety.
"On getting to the hospital, we are placed under a tighter security situation worse than what we have been witnessed in Nigeria. We are currently more confined than when we were in Nigeria, worse than prison setting.
"Contrary to what was agreed before our arrival, that our own personal doctors would supervise this treatment. Now they've changed the arrangement. So, we objected receiving treatment from strange doctors without the supervision of our own trusted physicians," he noted.
In the audio, the IMN leader said he wants to return to Nigeria to source for a reliable and trusted hospital among those countries that offer help.
"There are some other countries that volunteered to help which include Malaysia, Turkey," he said.