The Islamic Movement of Nigeria (IMN) says Sheikh Ibrahim Zakzaky has been transferred to an unknown location upon return from India where he sought medical treatment, only to face an "obstruction" in the procedure.

“We urge the security agency holding him hostage to declare to the public where they are keeping him in the country,” IMN spokesman Ibrahim Musa said in a statement.

Zakzaky returned to Nigeria along with his wife Mallimah Zinat -- who was also seeking treatment for injuries -- after announcing an early departure from India earlier on Thursday, citing obstruction of his treatment under the influence of the Nigerian government.

According to the statement and other media reports, Nigerian security agents “whisked” the religious leader away after he landed at the Abuja International airport “without allowing the multitude of journalists that were waiting for him for hours” to speak with him.

The IMN statement went on to detail the circumstances in which Zakzaky decided to discontinue his treatment in India, countering “the false claims" made by the Nigerian government.

It said Zakzaky and his wife had been transferred to India in a way that was greatly inappropriate for “patients suffering life threatening ailments” and not been allowed to rest between flights and upon arriving in India.

“However, despite their need for rest, they were forcibly wheeled to a hospital on arrival without their personal physician that accompanied them from Nigeria,” the statement read.

“There was even a report that the security agents in India subjected him to physical assault,” it added.

According to the statement, health workers took “selfies” with the sheikh and posted it on social media, in an act that violated their privacy.

It said Indian authorities had rejected any supervision of doctors previously familiar with Zakzaky’s case, restarting the medical evaluation and treatment process without their oversight.

“The Kaduna high court allowed the Sheikh to go to India with the government only supervising, instead the federal government presented him to the Indian government as a dangerous suspect with an unknown ailment coming to India and demanded stringent security placed on him,” read the statement.

“It was at this point that Sheikh Zakzaky lost confidence in the whole process and refused any further attempt to have him forcibly treated,” the statement added.

The top Muslim cleric and his wife were injured in a deadly military raid in 2015. They had been in prison until last week for four years despite a high court ruling granting them freedom.

The house of the 66-year-old cleric was raided in 2015 after the Nigerian government alleged that his supporters had blocked a convoy of the country’s defense minister. The movement has categorically rejected the allegation.

During the raid, Sheikh Zakzaky was beaten and lost his left eye. His wife sustained serious wounds, and three of his sons and more than 300 of his followers were killed.

The couple were put in custody afterwards. A Nigerian court granted the Muslim cleric bail last week so that he could fly to India for treatment.