SEOUL - Republic of Korea (ROK) on Monday called on the Democratic People's Republic of Korea (DPRK) to retract its unilateral move to annul a business deal with a ROK company.

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The DPRK announced last Friday it could revoke an exclusive contract with a ROK conglomerate over tours to Mount Kumgang, citing "no more prospect of resuming" the tours, suspended since 2008 after a shooting death of a South Korean tourist there.

"North Korea (DPRK)'s unilateral claim is an illegitimate, unjust move" violating agreements between the two countries and business partners, Chun Hae-sung, spokesman of Seoul's unification ministry, told reporters. "The claim should be immediately renounced."

The government will work closely with Hyundai Asan, the tour operator, and take "necessary" measures, Chun added without elaborating.

Observers say Pyongyang's move is in response to Seoul's reluctance to lift its ban on the tours, which had brought nearly two million ROK people to the scenic mountain since 1998 and served as a source of hard cash.

Pyongyang has long called for a resumption of the tours, but Seoul insisted on addressing unresolved issues, including future safety guarantees for ROK tourists and a joint investigation into the shooting death, before reopening the tours.

The two Koreas have only confirmed their differences at their working-level talks last year over reviving the lucrative tourism deal.