(File photo)

PYONGYANG, June 28 (Xinhua) -- The Democratic People's Republic of Korea (DPRK) said Wednesday it would impose the death penalty on those involved in an assassination plot against its top leader Kim Jong Un.

Those involved in the assassination plot included former South Korean President Park Geun-hye, said a joint statement by the DPRK Ministry of State Security, the Ministry of People's Security and the Central Public Prosecutor's Office.

"We declare at home and abroad that we will impose the death penalty on traitor Park Geun-hye," said the statement, which was released as "the enemies' moves to stifle the DPRK at any cost have reached an extremely grave phase."

The former director of South Korea's National Intelligence Service (NIS) Lee Byung-ho would meet a similar fate, it added.

The supreme leadership of the DPRK is a symbol of the dignity and might of the DPRK, said the statement, adding that "all those who organized, took part or pursued state-sponsored terrorism targeting the supreme leadership of the DPRK are subject to criminal prosecution irrespective of nationality."

The DPRK also demanded the immediate handover of Park by South Korea or it would face an "adverse effect" in relations with the North if Seoul refuses to do so, according to the statement.

The DPRK has got enough evidence to prove that Park started plotting to kill Kim since late 2015, said the statement.

Park signed a specified operation plan of the NIS made with the support of the Central Intelligence Agency (CIA) to kill Kim through a car crash or train derailment, it said.

Pyongyang said it had foiled a plot in April to kill Kim during mass celebrations by NIS and CIA agents who have infiltrated into the DPRK.

The agents were all arrested and confessed to the crime. The method to kill Kim also included using biochemical and radioactive material when he appeared in public, said DPRK officials.

"There have been a series of revelations of state-sponsored terrorism of the enemies targeting the supreme leadership of the DPRK," said the statement, which was carried by local media.

"A revelation showed that Park Geun-hye of South Korea pushed forward the operation of 'removing the north's leadership' in collusion with the (National) Intelligence Service during her tenure, in the wake of the detection of a group of hideous terrorist criminals who were infiltrated by the CIA and puppet (N)IS into the DPRK for the purpose of state-sponsored terrorism against its supreme leadership with the use of bio-chemical substance," it said.

"This is touching off the surging indignation of the army and people of the DPRK," it added.

The statement also said that Park had pushed forward the "operation to replace the supreme leadership of the north" in secrecy since the end of 2015 and the "assassination" plot was included in the secret operational plan that was spearheaded by the NIS.

"At that time Park ignored the experts' report that 'the north's regime change will be difficult' but welcomed the (N)IS report to the effect that 'the situation is unstable in the north and therefore, regime change can be possible' and examined the (N)IS secret operational plan targeting 'replacement of the north's leadership' and directly signed it," said the statement.

"They even thought of disguising the operation as a car or train accident ... But the plan was not put into practice under strict vigilance in the north and afterwards, the secret operational plan was automatically scrapped with Park Geun-hye's impeachment that led to the regime change in the south," it said.

"We officially declare that if the U.S. and the South Korean puppet forces again attempt at state-sponsored terrorism against the supreme leadership of the DPRK, we will track down those who organized, took part in and pursued the plot and carry out the summary execution of them without advance notice under wartime law," it said.