Dr Mahathir Mohamad has called for the immediate release of Anwar Ibrahim, describing the latter as a prisoner of conscience.

He made the call in a joint statement with US-based human rights lawyer Kimberly Motley.

Mahathir considered Anwar a political prisoner who has endured more than 34 months in prison and is now in need of comprehensive medical care.

The former premier's call, however, left Gerakan Youth chief Tan Keng Liang puzzled.

“Why didn't Mahathir call for the release during his time as prime minister? Why only now after defecting to the opposition? What's the difference between now and then?” he asked on Twitter.

Tan also added the hashtags “#puzzling #mystery #weird”.

Almost two decades ago, Anwar, who was then deputy prime minister, had accused Mahathir of authoring a political conspiracy against him and fabricating a charge of sexual misconduct.

Mahathir, on the other hand, claimed that Anwar, whom he sacked from government in 1998, lacked the moral fibre to lead the nation.

The two have since buried the hatchet in their campaign against Prime Minister Najib Abdul Razak.

Anwar is currently serving a five-year jail term for a second sodomy charge, which he claims was fabricated as well by the Najib administration.

Mahathir, who is the chairperson of Pakatan Harapan, and Motley, who is in Kuala Lumpur, held a meeting yesterday to discuss Anwar's current position.

“We had a fruitful meeting. We jointly agree Anwar should be unconditionally released from prison immediately. He is currently in hospital, undergoing long-term medical treatment.

“Anwar is a political prisoner and has endured more than 34 months in prison.

“He is scheduled for release in June 2018 and his current medical state is of concern to his family, friends, and people around the world,” the two said in the joint statement this afternoon.

Mahathir and Motley said Anwar, as a 70-year-old prisoner of conscience, requires significant medical care, which has been hampered due to his incarceration.

“We urge the government to consider our request seriously and for the sake of justice and the international relations of Malaysia,” they added.