Some 1,000 workers at Daewoo Motor's main plant walked out Tuesday to protest against the arrest of their union executives, labour union officials said. An official for the company said the walkout had stopped production at its main plant at Puchon, west of Seoul. Early in the morning, police stormed Daewoo's main plant near Seoul and took 20 unionists into custody, the union official said. A Puchon police spokesman said seven unionists were being held for obstruction of duties - a charge referring to leading workers off the job - and the others had been released.