The death of Kim Jong-nam has escalated into a diplomatic row between North Korea and Malaysia, with the Southeast Asian country recalling its ambassador from Pyongyang after the regime's ambassador in Kula Lumpur questioned the impartiality of the investigation into Kim.
Malaysia's police chief, Khalid Abu Bakar, said both officials were in Malaysia but could not confirm if they were in the North Korean embassy.
Malaysian police said they also were questioning a senior official at the North Korean embassy and a staffer at its state airline, Free Malaysia Today reported.
A statement released by North Korea's embassy on Wednesday in Kuala Lumpurdismissed the police account of Kim Jong-nam's death, describing two women held as "innocent".
Police say the women - one of them Indonesian, the other Vietnamese - washed their hands soon after poisoning Kim, the long-estranged half brother of the North Korean ruler.
"This will definitely help solve several issues as so far none of the deceased's family members have come forward despite several media reports which claimed they have". The Malaysian Ministry of Foreign Affairs announced on February 20 that it had recalled its ambassador to Pyongyang Mohammad Nizan Bin Mohammad "for discussions".
But North Korea insisted the women were telling the truth.
Hwang also instructed his government to strengthen vigilance and precautions against possible North Korean terrorist attacks on the government and citizens of South Korea.
Earlier, the Malaysian response to the ambassador's press conference had been equally blunt, with Foreign Minister Anifah Aman saying North Korea's complaints were based on "delusions, lies and half-truths".
Malaysian police say they know who orchestrated the attempted break-in, but wouldn't provide a name.
Mr Kim became dizzy and unwell after one woman stood in front of him in the busy departure hall to distract him, as the second accomplice approached him from behind, pulled a cloth from a blue handbag, reached around his head and pressed it onto his face.
Investigators believe a toxic, liquid rubber was applied to Kim Jong Nam's face, which was lethal enough to kill him. "At the moment we can not trust the investigation by the Malaysian police", ambassador Kang Chol told reporters after talks at the foreign ministry.
Siti Aisyah, 25, Indonesian, the other female suspect.
The director of general health at Malaysia's health ministry said on Tuesday the exam showed no evidence of a heart attack or anything that suggested wounds to the body.
It is widely believed North Korea was behind the attack.
North Korea has refuted reports that the victim was Kim Jong-nam.
Kim Jong-Nam was once thought to be the natural successor to his father, the then-North Korean leader Kim Jong-Il.
The attack "showed the reckless and brutal nature of the North Korean government", South Korean Prime Minister Hwang Kyo-ahn said Monday during a National Security Council meeting.
Malaysia is among a dwindling number of Cold War-era friends with which North Korea - which has 53 embassies and other foreign missions, according to South Korean government data - has managed to keep up ties.