After a lengthy trial, Doan Thi Huong pleaded guilty last month to a lesser charge of "causing injury" over the 2017 assassination of Kim Chol, believed to be the North Korean leader's half-brother Kim Jong-nam, making her the only person convicted for a murder that made headlines around the world.

Weeks earlier, Indonesian Siti Aisyah -- the only other person to face trial over the killing carried out with a banned nerve agent at Kuala Lumpur airport was released and flew home after her murder charge was withdrawn.

The pair always denied having committed murder, arguing that they were pawns in a plan hatched by North Korean agents who fled Malaysia after the killing.

South Korea accused Pyongyang of plotting the assassination.

Huong, who received a jail term of several years, which was cut due to sentence remissions, was freed from a prison outside the Malaysian capital at about 7:20 a.m. (2320 GMT Thursday), her lawyer Hisyam Teh Poh Teik told AFP.

Journalists waiting outside the jail saw a van and a car with tinted windows race past, and a court official at the scene also confirmed Huong had been released.

Speaking ahead of her release, Hisyam had said she was "definitely looking forward to going home".

The 30-year-old former hair salon worker was expected to head to an immigration office in administrative capital Putrajaya to sort out documentation, before flying to Vietnam in the evening.

'True killers escaped justice'

While there is relief for the women -- who said they believed they were taking part in a TV show prank -- those behind the plot are unlikely to ever face justice.

"The assassins have not been brought to justice," said Hisyam, adding the women's legal teams consistently argued their North Korean handlers were the real murderers.

The pair were arrested after they were captured on airport CCTV cameras walking up behind Kim, as he waited for a flight, and one was seen clasping her hands over his face.

Aisyah and Huong were put on trial for murder in October 2017 and faced death by hanging if convicted.

The defense stage of the case was due to start in March, but in a shock move, prosecutors announced they were withdrawing the murder charge against Aisyah, 27, and she flew back to Jakarta.

Her release followed intense diplomatic pressure from Indonesia, including from President Joko Widodo.

Vietnam then stepped up pressure for Huong's murder charge to be dropped. Their initial request was refused, but at the start of April prosecutors offered her a reduced charge, paving the way for her release.

The assassination sparked a furious row between North Korea and Malaysia, previously one of nuclear-armed Pyongyang's few allies, and prompted both countries to expel each other's ambassadors.

Ties have improved in recent times however with Malaysia saying it plans to re-open its embassy in Pyongyang, which was closed shortly after the murder.