The United States has expressed respect and admiration for the professionalism of Malaysian law enforcement authorities with regard to their handling of the murder of Kim Jong-nam.

In a statement, US assistant secretary of state for East Asian and Pacific Affairs Daniel Russel said Malaysian law enforcement agencies conducted an impressive investigation, as well as worked from the facts in a quick, professional and sophisticated manner.

“The hijacking of the territory of a country by a foreign power for the purpose of murder - for the purpose of political assassination - is reprehensible and my sympathies go to Malaysia on that account,” Russel said.

He said the current diplomatic row between Malaysia and North Korea is regrettable, but understood the reason for Malaysia expelling the North Korean ambassador.

“I fully understand the actions taken by the foreign minister and the prime minister of Malaysia in their decision to exercise their right under the Vienna Convention to declare a diplomat, who refuses to cooperate with a legitimate and lawful request by the host government, persona non grata and to order his expulsion,” Russel added.

The assistant secretary also shared the concerns of the Malaysian government with respect to the welfare of Malaysians in North Korea.

“The US has itself some unfortunate examples of American citizens detained in North Korea. There are some, as I speak.

“I can only hope that there is a quick and satisfactory resolution of the issues between Malaysia and the DPRK (North Korea),” he added.

On Tuesday, North Korea announced that Malaysians would not be allowed to leave the republic, prompting Prime Minister Najib Abdul Razak to order a similar ban on North Koreans leaving Malaysia.

Najib also condemned North Korea for its move, which he claimed was tantamount to holding the Malaysians hostage.

There are 11 Malaysians in North Korea, including embassy staff and their families.

Police have charged two women, an Indonesian and Vietnamese national, for Jong-nam's murder.

The two were accused of smearing the deceased, who is the estranged half-brother of North Korean leader Kim Jong-un, with VX nerve agent at the KL International Airport 2 (KLIA2) on Feb 13.

North Korea has accused Malaysia of fabricating evidence and colluding with outside forces, allegations that led to the expulsion of its ambassador.