South Korean officials called the claim "groundless". The CIA declined to comment, as is customary.
But North Korea isn't letting it go. Last week, it said the US and South Korea should "execute" those involved in the purported plot. On Thursday, it demanded that the United States and South Korea hand over the "terror suspects". "The Central Prosecutor's Office will ask for the handover of those criminals and prosecute them under the relevant laws," North Korean Vice Foreign Minister Han Song Ryol told foreign diplomats and reporters in Pyongyang, according to China's Xinhua News Agency.
No details were included about who the suspects are and how many are on the run.
Without this information, it's hard to evaluate Pyongyang's allegations - or even take them very seriously.
But it's worth noting that North Korea has a long history of its own ripped-from-a-bad-movie assassination plots. Or, as the Associated Press put it, "In the paranoid universe of North Korea, the feverish accusations it makes against its sworn enemies bear a creepy resemblance to its own misdeeds."
There was, for example, the 1968 attempt to kill South Korea's President. North Korea sent a 31-person commando team over the border to execute a siege on the leader's residence. The team was discovered by some teenage brothers and never completed the mission.
In 1997, a member of Kim Jong Un's extended family who defected was fatally shot on a South Korean street by assailants from the North.
In 2009, Pyongyang allegedly paid about US$40,000 ($58,580) to have dissident Hwang Jang Yop, secretary of North Korea's ruling Workers' Party until he defected in 1997, killed. The attempt was unsuccessful.
In 2011, a defector to South Korea suspected of being a North Korean secret agent was arrested on suspicion of attempting to assassinate Park Sang Hak, an outspoken critic of the Pyongyang regime. South Korean authorities said the suspected agent had set up a meeting with Park in a subway station in Seoul and planned to kill him with a poison pen.
And, most recently, the North Korean regime has been widely blamed for the death of Kim Jong Nam, the estranged older half-brother of Kim Jong Un.
Malaysian authorities said he was attacked by two women at the Kuala Lumpur airport; one grabbed him and the other covered his face with a cloth doused in some kind of liquid. He died on the way to the hospital.Washington Post