Embattled former Khmer National United Party President Nhek Bun Chhay has been released from prison under court supervision.

PJ Prison Director Pich Yun, following the directions of the Phnom Penh Municipal Court, said Bun Chhay left the prison at about 9pm on Monday. He had previously said that he didn't expect Bun Chhay’s release until at least Tuesday morning.

“We were afraid that [health] problems would happen to him if he is not released,” Yun said.

The court document, signed on Monday and released by government mouthpiece Fresh News, ordered the prison to release him under supervision of the court.

Bun Chhay was arrested in August last year in relation to a 2007 drug case and a drug bust in 2012, and was charged with conspiracy to produce drugs and importing drug components.

He had appeared to fall from grace in June after the leak of a phone call with then-opposition lawmaker Eng Chhay Eang in which Bun Chhay pledged to urge his supporters to vote for CNRP commune council candidates in areas where the KNUP was not running.

Bun Chhay was summarily stripped of his role as a government adviser after the poll and was arrested two months later. Given the time elapsed since the raid, the arrest was widely suspected to be politically motivated.

Prior to his role as KNUP’s president, Bun Chhay was a military commander in the coalition government under Funcinpec and CPP.

Bun Chhay’s assistant, Mak Chhea, said on Monday night that he could not comment.

“I am driving very fast to get him,” he said.

Court spokesperson Y Rin confirmed the authenticity of the warrant, but declined to provide details.

“Mr Nhek Bun Chay was decided by the judge to be allowed outside detention but put under court monitoring,” he said. “He needs to follow some conditions. The release was made in accordance with his lawyer’s request.”

In other cases, conditions of supervision have included regularly appearing in court and requesting permission before going abroad.

Current KNUP president Sing Kiri said on Tuesday Bun Chhay would eventually take over his position once his health improved, though he declined to specify the severity or nature of the health problems.

“Mr Nhek Bun Chhay will return to be president of the KNUP,” he said. “But because of his health, we have not set the date for becoming the president yet. He needs to treat his health first and to relax to get recovery.”