The National Intelligence Service(NIS) launched an attempt to raid the headquarters of the Korean Confederation of Trade Unions(KCTU) in Seoul on Wednesday morning.

The move came after the NIS acquired a warrant to search the union’s headquarters as part of its probe into allegations that some KCTU members violated the National Security Act.

The KCTU is blocking investigators and police officers from entering the office while voicing the need for the raid to be conducted in the presence of its lawyers as it livestreams the standoff.

The NIS also began raiding the office of the Korean Health and Medical Workers' Union in Seoul on Wednesday.

The spy agency said it obtained warrants for the raids after securing related evidence in a case they’ve been working on for years, which is likely related to a National Security Act violation committed by a progressive figure in Jeju.