Police raided offices of a major construction workers' union Friday over allegations that the union provided illegal political funds to a minor progressive party ahead of the 2020 parliamentary election.

The Seoul Metropolitan Police Agency sent investigators to two branch offices of the Korean Construction Workers' Union and eight other locations to seize evidence, including account books and computer hard disks, according to officials.

The KCWU, affiliated with the Korean Confederation of Trade Unions -- one of South Korea's two biggest umbrella unions -- was accused of giving a total of 60 million won ($46,518) to the left-wing Minjung Party, now renamed the Progressive Party, ahead of the 2020 parliamentary election.

Police accuse executives of the KCWU of having rank-and-file union members provide donations to the party out of the union's funds to make it look as if they made the donations individually on their own.

By law, political donations out of the funds of a corporate entity or an organization are prohibited. (Yonhap)