Bankrupt Kia Motors Corp. of South Korea ordered its plants locked for 10 days as negotiations with striking workers failed to make progress. However, Kia's 20,000-member labor union said its members would continue to go to their workplaces to picket. Kia, once the nation's second-largest auto maker, is in court receivership after going bankrupt last July under the weight of $1 billion in bank debt. The government, Kia's largest stockholder, said last month that it would soon announce a schedule to sell the car maker at auction. Kia workers then walked off their jobs, demanding that the company pay overdue wages and guarantee job security. Kia's management rejected the union's demands.