Royal Malaysian Police personnel keep watch behind a police line drawn across the entrance to the North Korean embassy in Kuala Lumpur on March 7, 2017, following a directive barring North Korean embassy staff from leaving the country. 
Malaysia said March 7 that North Korea embassy staff are barred from leaving the country, in a tit for tat response after Pyongyang banned all Malaysian citizens from leaving.  / AFP PHOTO / MOHD RASFAN        (Photo credit should read MOHD RASFAN/AFP/Getty Images)
MOHD RASFAN/AFP/AFP/Getty Images
Royal Malaysian Police personnel keep watch behind a police line drawn across the entrance to the North Korean embassy in Kuala Lumpur on March 7, 2017, following a directive barring North Korean embassy staff from leaving the country. Malaysia said March 7 that North Korea embassy staff are barred from leaving the country, in a tit for tat response after Pyongyang banned all Malaysian citizens from leaving. / AFP PHOTO / MOHD RASFAN (Photo credit should read MOHD RASFAN/AFP/Getty Images)
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Two women pleaded not guilty on October 2 to murdering the half-brother of North Korea's leader at the start of their trial in Malaysia, as prosecutors alleged they practised for the Cold War-style assassination before carrying it out. / AFP PHOTO / MOHD RASFAN        (Photo credit should read MOHD RASFAN/AFP/Getty Images)
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Royal Malaysian Police escort Vietnamese defendant Doan Thi Huong (2nd L) after her trial at the Shah Alam High Court in Shah Alam, outside Kuala Lumpur on October 2, 2017, for her alleged role in the assassination of Kim Jong-Nam, the half-brother of North Korean leader Kim Jong-Un. Two women pleaded not guilty on October 2 to murdering the half-brother of North Korea's leader at the start of their trial in Malaysia, as prosecutors alleged they practised for the Cold War-style assassination before carrying it out. / AFP PHOTO / MOHD RASFAN (Photo credit should read MOHD RASFAN/AFP/Getty Images)
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REMOVES REFERENCE TO RE-ENACTMENT - Vietnamese Doan Thi Huong is escorted by police as she arrives at Kuala Lumpur International Airport in Sepang, Malaysia, Tuesday, Oct. 24, 2017.  The two women accused of killing Kim Jong Nam, the North Korean leader's half brother, are touring at the Malaysian airport as participants in the murder trial visit the scene of the attack. (AP Photo/Sadiq Asyraf)
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REMOVES REFERENCE TO RE-ENACTMENT - Vietnamese Doan Thi Huong is escorted by police as she arrives at Kuala Lumpur International Airport in Sepang, Malaysia, Tuesday, Oct. 24, 2017. The two women accused of killing Kim Jong Nam, the North Korean leader's half brother, are touring at the Malaysian airport as participants in the murder trial visit the scene of the attack. (AP Photo/Sadiq Asyraf)
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In a picture taken on June 4, 2010 Kim Jong-Nam, the eldest son of North Korean leader Kim Jong-Il, waves after an interview with South Korean media representatives in Macau.  Kim Jong-Nam was in the limelight with Seoul's JoongAng Ilbo newspaper carrying a snatched interview with him at a hotel in Macau. Jong-Nam declined knowledge of the warship incident, it reported, and said his father is "doing well".  North Korean Leader  Leader Kim Jong-Il on June 7 attended a rare second annual session of parliament at which Kim's brother-in-law was promoted and the country's prime minister was sacked, state media reported.  REPUBLIC OF KOREA OUT  AFP PHOTO / JOONGANG SUNDAY VIA JOONGANG ILBO (Photo credit should read JoongAng Sunday/AFP/Getty Images)
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In a picture taken on June 4, 2010 Kim Jong-Nam, the eldest son of North Korean leader Kim Jong-Il, waves after an interview with South Korean media representatives in Macau. Kim Jong-Nam was in the limelight with Seoul's JoongAng Ilbo newspaper carrying a snatched interview with him at a hotel in Macau. Jong-Nam declined knowledge of the warship incident, it reported, and said his father is "doing well". North Korean Leader Leader Kim Jong-Il on June 7 attended a rare second annual session of parliament at which Kim's brother-in-law was promoted and the country's prime minister was sacked, state media reported. REPUBLIC OF KOREA OUT AFP PHOTO / JOONGANG SUNDAY VIA JOONGANG ILBO (Photo credit should read JoongAng Sunday/AFP/Getty Images)
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Story highlights

This is the first time Malaysia has blamed North Korea for Kim's murder

Diplomatic relations have soured between the two countries

CNN —  

For the first time, Malaysian Prime Minister Najib Razak has directly accused North Korea of murdering Kim Jong Nam.

It comes amid a deepening diplomatic row over the February killing of North Korean leader Kim Jong Un’s half-brother at Kuala Lumpur International Airport 2.

“What we are facing now is the result of their action in assassinating their own citizen in Malaysia, on Malaysian soil, using a strictly banned chemical weapon,” Najib told state media agency Bernama Wednesday.

A press official for Najib confirmed the comments to CNN. North Korea has repeatedly denied any involvement in Kim Jong Nam’s murder.

Kim died on February 13, fewer than 20 minutes after two women wiped his face with the highly toxic VX nerve agent, according to Malaysian police.

The ensuing investigation into Kim’s murder has severely damaged diplomatic relations between the two countries.

A new low was reached Tuesday when North Korea barred Malaysian nationals inside the country from leaving. Malaysia swiftly followed suit.

Until Wednesday, only South Korea’s intelligence agency had publicly linked North Korea to the killing, which it said was carried out on the orders of leader Kim Jong Un.

Najib’s comments could complicate efforts to secure the return of 11 Malaysian nationals held in North Korea.

They include four embassy staff members, their families and two UN employees – a man and a woman who work for the World Food Programme, according to the UN.

Malaysia says their 11 citizens are free to live their daily lives but are not free to leave.

Those wanted

Malaysia believes three people wanted for questioning in connection to Kim’s murder are holed up in the North Korean embassy in Kuala Lumpur.

Police say North Korea is not complying with its request to question them.

Only two people, a woman from Vietnam and another from Indonesia, have been formally charged with Kim’s murder.

Authorities from both countries have said the women believed they were participating in a prank TV show, but Malaysian authorities do not believe that’s true.

Siti Aisyah from Indonesia (left) and Doan Thi Huong from Vietnam have been charged with Kim's murder.
daniel chan/ap
Siti Aisyah from Indonesia (left) and Doan Thi Huong from Vietnam have been charged with Kim's murder.

A third North Korean who was in custody was released after investigators determined there wasn’t enough evidence to charge him. He was then deported back to North Korea.

Malaysia is seeking four other suspects in relation to the killing, all North Korean men who are believed to be back in Pyongyang.

Police said Tuesday North Korea had not responded to requests to hand them over. They have requested assistance from Interpol, the international police service.

CNN’s Zahra Ullah and journalist Salhan K. Ahmad contributed to this report