The Government department has also said it will impose additional sanctions on North Korea over the assassination.
VX, short for ‘venomous agent X’, has been banned by the United Nations, but analysts believe North Korea has one of the largest stockpiles in the world.
Kim’s estranged half-brother, Kim Jong Nam, was killed at the airport in Kuala Lumpur after two women smeared his face with VX.
The estranged half-brother of North Korea’s dictator had spoken out publicly against his family’s dynastic control of the isolated, nuclear-armed nation.
US State Department spokeswoman Heather Nauert said the US made the determination on February 22 under the Chemical and Biological Weapons Control and Warfare Elimination Act of 1991.
She added additional sanctions on North Korea went into effect earlier this week after the finding was formally published.
More to follow…