North Korea has demanded the extradition of South Korea's spy chief, after accusing him of being behind a plot to assassinate N Korean leader Kim Jong Un.
On Friday, North Korea's Central Prosecutor's Office (CPO) said South Korean intelligence service chief Lee Byung-ho was the mastermind behind a plot with the CIA to kill Kim Jong Un with a biochemical weapon.
"We urge the relevant authorities to immediately detect and arrest and hand over to the DPRK the masterminds of the hideous state-sponsored crime, accomplices and their followers," the CPO said.
Mr Byung-ho would face severe punishment for his actions, North Korea says.
"A Korean-style, anti-terrorist offensive will be commenced to mop up the intelligence and plot-breeding organizations of the U.S. and South Korea," North Korea's UN mission said in a Thursday statement, labelling the plot a "declaration of war".
South Korea has denied any involvement in a plot.