A Vietnamese woman who spent more than two years in a Malaysian prison on suspicion of killing the half-brother of North Korean leader Kim Jong-un has been freed.

Key points: Ms Huong had been jailed for more than three years after pleading guilty to causing harm but had her sentence reduced for good behaviour

Ms Huong had been jailed for more than three years after pleading guilty to causing harm but had her sentence reduced for good behaviour Her Indonesian co-accused was freed in March after high-level lobbying from Jakarta

Her Indonesian co-accused was freed in March after high-level lobbying from Jakarta Both women maintain they thought they were part of a prank and US and South Korean authorities say North Korea was behind the assassination

Doan Thi Huong, 30, was charged along with an Indonesian woman with poisoning Kim Jong-nam by smearing his face with liquid VX, a banned chemical weapon, at Kuala Lumpur airport in February 2017.

Malaysian prosecutors dropped a murder charge against Ms Huong last month after she pleaded guilty to an alternate charge of causing harm.

She was sentenced to three years and four months in jail for her role in Mr Kim's death, but in April received a one-third reduction for good behaviour.

Before leaving the courtroom after the hearing last month she told reporters she was happy and hoped to be a singer and actress when she returned to Vietnam.

Ms Huong was the only suspect in custody after the Attorney-General's stunning decision to drop a murder charge against her co-accused, Siti Aisyah, who was freed on March 11 after high-level lobbying from Jakarta.

Sorry, this video has expired CCTV footage of the assassination of Kim Jong-nam.

Ms Huong had sought to be acquitted after Ms Aisyah was released, but prosecutors rejected her request.

What is VX gas? A highly toxic and rapidly acting chemical warfare agent developed in the UK in the 1950s

A highly toxic and rapidly acting chemical warfare agent developed in the UK in the 1950s The most potent of all nerve agents, it is much more potent than the well-known sarin but works in a similar way

The most potent of all nerve agents, it is much more potent than the well-known sarin but works in a similar way Symptoms appear within seconds of exposure to the vapour or after exposure to the liquid form

Symptoms appear within seconds of exposure to the vapour or after exposure to the liquid form A large dose of VX may result in convulsions, loss of consciousness, paralysis and respiratory failure possibly leading to death

A large dose of VX may result in convulsions, loss of consciousness, paralysis and respiratory failure possibly leading to death It is possible that any visible VX liquid contact on the skin, unless washed off immediately, would be lethal

It is possible that any visible VX liquid contact on the skin, unless washed off immediately, would be lethal Only one person has ever been officially confirmed as having died from VX *Source: Centres for Disease Control and Prevention

She will return to Vietnam later on Friday, Mr Teh said.

After being released from prison, Ms Huong was taken into immigration custody immediately and will remain there before boarding a flight to Hanoi, the Vietnamese capital.

Vietnamese embassy translator Maridam Yacfar told reporters at the prison that Ms Huong looked "happy", but could not give further details.

Mr Teh said his client was very joyful when he met her at the prison.

"She was smiling from ear to ear," he said.

"She is looking forward to return home to meet her family and friends."

South Korean and US officials have said the North Korean regime had ordered the assassination of Mr Kim, who had been critical of his family's dynastic rule.

Pyongyang has denied the allegation.

Kim Jong-nam was belived to have been cast out of North Korea by his father Kim Jong-il. ( AP: Shin In-seop/JoongAng Ilbo, File )

Defence lawyers have maintained the women were pawns in an assassination orchestrated by North Korean agents.

The women said they thought they were part of a reality TV prank show and did not know they were poisoning Mr Kim.

Four North Korean men were also charged but they left Malaysia hours after the murder and remain at large.

Malaysia came under criticism for charging the two women with murder — which carries a mandatory death penalty in the South-East Asian country — when the key perpetrators were still being sought.

Kim Jong-nam was the eldest son in the current generation of North Korea's dynastic rulers but was believed to have been cast out by his father and had lived abroad for years.

He reportedly never met current leader Kim Jong-un, who is widely believed to have perceived his older sibling as a threat and targeted him for assassination.

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