Malaysia has recalled its envoy to Pyongyang in an escalating row over the killing of Kim Jong-nam, the half-brother of North Korea's leader Kim Jong-un, BBC reports. 

Kim Jong-nam died in mysterious circumstances last week at a Kuala Lumpur airport - police believe he was poisoned while waiting for a flight.

Malaysian police say they are now looking for four North Koreans.

Pyongyang's envoy to Malaysia was also summoned over earlier comments he made.