By Kang Shinhye

SEOUL, Apr 12 (Reuters) With farmers storming a warehouse filled with American grain, South Korea managed to sell only 302 tonnes of U.S. rice at an auction on Wednesday as many buyers were again too worried about protests to join the bidding.

The Korea Agro-Fisheries Trade Corporation had been looking for better results after selling only 40 tonnes of the 1,372 tonne total last week.

The state agency will try again next week to auction off the rice but the poor results continues to raise doubts over whether Seoul can meet obligations to open up its market to foreign competition.

''We are still worried about the protests of farmers and will stay on the sidelines until we think it will be safe,'' said one wholesaler who asked not to be identified.

A few South Korean farmers in recent months have killed themselves by drinking agricultural chemicals in protest against opening the domestic market to imported rice.

Farmers and activists have also set fires and armed themselves with steel rods as they charged lines of riot police in rallies against the imports.

The trade corporation did not disclose buyers in order to protect bidders. Retailers have also stayed away, meaning the rice will not end up on store shelves, for now.

The little rice that was sold will likely end up at restaurants and served to consumers who do not know they are eating the imported food or to places that make processed food.

''Buyers are staying away from the U.S. rice auction because they are afraid of violent farmers and protests,'' said an official of the trade corporation, adding storage costs are growing with each failed auction and more product is arriving.

The U.S. rice has been kept under guard in locations that were supposed to be secret but a group of farmers and activists stormed a warehouse on Wednesday in Seoul and were tearing open bags of the American grain until warehouse personnel forced them out, police said.

South Korea's parliament approved a deal last year with rice exporters to open the market slightly wider for foreign imports and allow for the first direct sales to consumers.

In the deal with rice exporters, Seoul said it will incrementally increase its imports of foreign rice from 4.4 percent of total consumption in 2005 to 8 percent of total consumption by 2014.

South Korea struck the deal to avoid more drastic measures to open its markets more quickly.

Although South Korean rice is about four times more expensive than U.S. rice on commodities markets, South Korean authorities will levy heavy taxes on imported U.S. rice that virtually eliminates any cost advantage at the retail level.

REUTERS PV HT1645