Media playback is unsupported on your device Media caption Why was North Korea's Kim Jong-nam killed?

Malaysia has expelled North Korea's ambassador after he criticised its investigation into the killing of the North Korean leader's half-brother.

Kang Chol must leave within 48 hours, Malaysia's foreign ministry says.

It demanded an apology after the envoy said North Korea could not trust Malaysia's handling of the inquiry, but says it did not receive one.

Kim Jong-nam, the half-brother of Kim Jong-un, died three weeks ago at a Kuala Lumpur airport.

Malaysia has not directly blamed North Korea for the attack, in which two women smeared the nerve agent VX on Mr Kim's face. But there is widespread suspicion Pyongyang was responsible.

Mr Kang, who had become a fierce critic of his host country, said the inquiry into the killing had become "politicised" and was being interfered with.

The Malaysian Foreign Minister, Anifah Aman, declared the ambassador "persona non grata" and said his country had demanded an apology for the comments, but this was not forthcoming.

"Malaysia will react strongly against any insults made against it or any attempt to tarnish its reputation," Mr Anifah said in a statement.

The North Korean representative also failed to turn up for a meeting at the Malaysian foreign ministry on Saturday, he added.

Image copyright Reuters Image caption North Korea's ambassador was declared "persona non grata" by Malaysia

Malaysia is seeking to question several North Koreans, including an embassy official, over the death of Kim Jong-nam.

Two women, one from Vietnam and another from Indonesia, have been charged with murder. They both said they thought they were taking part in a TV prank but are yet to make a formal plea in their case.

The expulsion of the envoy also comes after the government announced an investigation into a company called Glocom, which has been operating in Malaysia for several years.

According to a confidential UN report, Glocom is run by North Korea's top intelligence agency to sell military communications equipment, in violation of UN sanctions.

Earlier on Saturday, a North Korean suspect questioned in connection with the case was released due to insufficient evidence.

Malaysia was one of very few countries that had relatively friendly relations with North Korea.

But it cancelled visa-free travel for visiting North Koreans in the wake of the killing, citing security reasons. It had already recalled its ambassador in Pyongyang as it investigated the case.

North Korea has not yet confirmed that the body is that of Kim Jong-nam, acknowledging him only as a North Korean citizen. Mr Kim was travelling using a passport under a different name.