Updated

North Korea says it has arrested a South Korean spy in Pyongyang for allegedly trying to rally anti-government forces.

South Korean intelligence officials quickly called the North's claim Thursday ridiculous and groundless.

North Korea regularly accuses Seoul and Washington of trying to overthrow its secretive, authoritarian system but specific claims that an individual spy has been captured are somewhat unusual.

The few details in the statement by an unidentified spokesman for the North's state security ministry couldn't be independently verified. There was no statement from the alleged agent. There were no details about his condition or legal representation.

The North said the South Korean entered through a border country after six years of using religion to disguise espionage activities. Without elaborating, it said officials are "now intensifying investigation."