Malaysia is considering expelling North Korea's envoy to the Southeast Asian nation or shutting its embassy in Pyongyang, as tensions escalate over the killing of the estranged half brother of the North's leader, Kim Jong Un, a senior government official said.

Kim Jong Nam, 46, was killed at Kuala Lumpur International Airport on Feb. 13 with what police believe was a fast-acting poison, as he prepared to board a flight to Macau where he lived in exile with his family under the protection of Beijing.

North Korea's ambassador said last week his country "cannot trust" Malaysia's handling of the probe, and also accused the country of "colluding with outside forces" — a veiled reference to bitter rival South Korea.