The labor union of domestic tiremaker Kumho Tire has declared it will throw out the plan it drafted with the management to salvage the company in protest of plans to sell it to a Chinese firm.

The union held a news conference and rally in Gwangju on Saturday and vowed to fight to block the sale. 

The unionized workers said the creditors and Korea Development Bank were passing the blame on the failed management of Kumho Tire's Chinese plant to workers at home.

They said they will mobilize all possible means and do whatever it takes to block the creditors' plan to sell the firm to a foreign company. 

The union launched a partial two-hour strike for every shift on Saturday at its plants in Gwangju and Gokseong, South Jeolla Province. This will rise to four hours on Sunday with a full strike planned from Monday.

On the creditors' request, the management and union of Kumho Tire presented a plan earlier this week to normalize operations of the financially troubled firm, including a 20 percent wage reduction and seeking labor union consent in the case of an overseas sale. 

However, on Friday creditors and the Korea Development Bank announced plans to sell the firm to Chinese tiremaker Qingdao Doublestar by this year's first half.