SEOUL (AFP) - North Korea said Thursday a South Korean spy has been arrested while trying to use "dishonest elements" for a mission to destablise its social system.

Security authorities recently intercepted an agent of South Korea's intelligence service in Pyongyang, according to the North's official Korean Central News Agency (KCNA).

It quoted a spokesman for the Ministry of State Security as saying the man had confessed to coming into Pyongyang illegally through a third country.

"An initial investigation indicates that he was engaged in anti-DPRK (North Korea) espionage and plot-breeding activities in a third country bordering the DPRK for nearly six years, while disguising himself as a religionist," KCNA said.

The spy entered the North to "rally dishonest elements within the boundary of the DPRK and use them for undermining the stability of the social system in the DPRK", it said.

"This fully proves to what extent the puppet group of conservatives has reached in its anti-DPRK moves," it said.

North and South Korea have remained technically at war since their 1950-1953 conflict ended only in an armistice.

Since 1953, thousands of North Korean spies have been arrested in the South. The North has also sporadically announced the arrests of South Korean citizens on espionage charges.