Killing of Kim Jong Nam organised by North Korean ministries - South Korea

South Korean intelligence believes suspects wanted for the murder of the half-brother of North Korea's leader included several officials who worked for the reclusive state's foreign and security ministries, according to lawmakers in Seoul.

Kim Jong Nam was killed earlier this month at a Malaysian airport by assassins using VX nerve agent, a chemical capable of killing in minutes and listed by the United Nations as a weapon of mass destruction.

South Korea is acutely sensitive to developments in its unpredictable nuclear-armed neighbor, and intelligence agency officials have briefed lawmakers on the sensational killing of the estranged half-brother of the North's leader Kim Jong Un.

North Korea has not acknowledged his death. But South Korean and U.S. officials believe Kim Jong Nam, who had criticized his family's control of the isolated state, was assassinated by agents of the North.

"Among eight suspects in this case four are from the ministry of state security and two who actually took action are from the foreign ministry," Lee Cheol-woo, one of the lawmakers briefed by South Korean intelligence, told reporters.

"That is why it is a case of terrorism led by the state, directly organized by the ministry of state security and the foreign ministry," Lee added.

Malaysian police have identified a total of eight North Koreans as suspects or as wanted for questioning, including a North Korean embassy official believed to still be in Kuala Lumpur.

Malaysia's health minister Subramaniam Sathasivam said on Sunday that Kim Jong Nam died within 15-20 minutes of being assaulted by two women who are believed to have smeared VX on his face.

The women, Indonesian and Vietnamese citizens, are in police custody and have told officials from their respective embassies that they believed they were taking part in a TV prank.

Another South Korean lawmaker briefed by the intelligence agency, Kim Byung-kee, said the North Koreans had operated in three teams. Two teams were responsible for hiring women in Indonesia and Vietnam and bringing them to Malaysia to carry out the attack and another was a "back-up" team.

The killing has sparked a diplomatic standoff between the two usually friendly countries, with Malaysia refusing to hand over the body to North Korea before it is officially identified by the victim's next of kin.